diff --git a/package-lock.json b/package-lock.json
index 512e2dd..9eb6e88 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -11,12 +11,12 @@
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-      "resolved": "https://registry.npmjs.org/accepts/-/accepts-1.3.4.tgz",
-      "integrity": "sha1-hiRnWMfdbSGmR0/whKR0DsBesh8=",
+      "version": "1.3.7",
+      "resolved": "https://registry.npmjs.org/accepts/-/accepts-1.3.7.tgz",
+      "integrity": "sha512-Il80Qs2WjYlJIBNzNkK6KYqlVMTbZLXgHx2oT0pU/fjRHyEp+PEfEPY0R3WCwAGVOtauxh1hOxNgIf5bv7dQpA==",
       "requires": {
-        "mime-types": "2.1.17",
-        "negotiator": "0.6.1"
+        "mime-types": "~2.1.24",
+        "negotiator": "0.6.2"
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@@ -938,6 +938,15 @@
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       "integrity": "sha1-TJQj6i0lLCcMQbK97+/5u2tiwGo="
     },
+    "cache-content-type": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/cache-content-type/-/cache-content-type-1.0.1.tgz",
+      "integrity": "sha512-IKufZ1o4Ut42YUrZSo8+qnMTrFuKkvyoLXUywKz9GJ5BrhOFGhLdkx9sG4KAnVvbY6kEcSFjLQul+DVmBm2bgA==",
+      "requires": {
+        "mime-types": "^2.1.18",
+        "ylru": "^1.2.0"
+      }
+    },
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       "resolved": "https://registry.npmjs.org/camelcase/-/camelcase-4.1.0.tgz",
@@ -1040,9 +1049,19 @@
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-      "resolved": "https://registry.npmjs.org/content-disposition/-/content-disposition-0.5.2.tgz",
-      "integrity": "sha1-DPaLud318r55YcOoUXjLhdunjLQ="
+      "version": "0.5.3",
+      "resolved": "https://registry.npmjs.org/content-disposition/-/content-disposition-0.5.3.tgz",
+      "integrity": "sha512-ExO0774ikEObIAEV9kDo50o+79VCUdEB6n6lzKgGwupcVeRlhrj3qGAfwq8G6uBJjkqLrhT0qEYFcWng8z1z0g==",
+      "requires": {
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+      },
+      "dependencies": {
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+          "resolved": "https://registry.npmjs.org/safe-buffer/-/safe-buffer-5.1.2.tgz",
+          "integrity": "sha512-Gd2UZBJDkXlY7GbJxfsE8/nvKkUEU1G38c1siN6QP6a9PT9MmHB8GnpscSmMJSoF8LOIrt8ud/wPtojys4G6+g=="
+        }
+      }
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@@ -1055,12 +1074,19 @@
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-      "version": "0.7.1",
-      "resolved": "https://registry.npmjs.org/cookies/-/cookies-0.7.1.tgz",
-      "integrity": "sha1-fIphX1SBxhq58WyDNzG8uPZjuZs=",
+      "version": "0.8.0",
+      "resolved": "https://registry.npmjs.org/cookies/-/cookies-0.8.0.tgz",
+      "integrity": "sha512-8aPsApQfebXnuI+537McwYsDtjVxGm8gTIzQI3FDW6t5t/DAhERxtnbEPN/8RX+uZthoz4eCOgloXaE5cYyNow==",
       "requires": {
-        "depd": "1.1.1",
-        "keygrip": "1.0.2"
+        "depd": "~2.0.0",
+        "keygrip": "~1.1.0"
+      },
+      "dependencies": {
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+          "version": "2.0.0",
+          "resolved": "https://registry.npmjs.org/depd/-/depd-2.0.0.tgz",
+          "integrity": "sha512-g7nH6P6dyDioJogAAGprGpCtVImJhpPk/roCzdb3fIh61/s/nPsfR6onyMwkCAR/OlC3yBC0lESvUoQEAssIrw=="
+        }
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@@ -1191,10 +1217,10 @@
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       "integrity": "sha1-eOy4o5kGYYe7N07t412ccFZagD0="
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-    "error-inject": {
-      "version": "1.0.0",
-      "resolved": "https://registry.npmjs.org/error-inject/-/error-inject-1.0.0.tgz",
-      "integrity": "sha1-4rPZG1Su1nLzCdlQ0VSFD6EdTzc="
+    "encodeurl": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/encodeurl/-/encodeurl-1.0.2.tgz",
+      "integrity": "sha1-rT/0yG7C0CkyL1oCw6mmBslbP1k="
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@@ -1367,7 +1393,8 @@
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-          "bundled": true
+          "bundled": true,
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@@ -1410,7 +1437,8 @@
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+          "bundled": true,
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@@ -1423,6 +1451,7 @@
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           "bundled": true,
+          "optional": true,
           "requires": {
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@@ -1430,6 +1459,7 @@
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           "version": "2.10.1",
           "bundled": true,
+          "optional": true,
           "requires": {
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           }
@@ -1437,6 +1467,7 @@
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           "bundled": true,
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@@ -1444,7 +1475,8 @@
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+          "bundled": true,
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@@ -1458,30 +1490,36 @@
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+          "bundled": true,
+          "optional": true
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           "version": "1.0.5",
           "bundled": true,
+          "optional": true,
           "requires": {
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         "concat-map": {
           "version": "0.0.1",
-          "bundled": true
+          "bundled": true,
+          "optional": true
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-          "bundled": true
+          "bundled": true,
+          "optional": true
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           "version": "1.0.2",
-          "bundled": true
+          "bundled": true,
+          "optional": true
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         "cryptiles": {
           "version": "2.0.5",
           "bundled": true,
+          "optional": true,
           "requires": {
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@@ -1516,7 +1554,8 @@
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-          "bundled": true
+          "bundled": true,
+          "optional": true
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@@ -1543,7 +1582,8 @@
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+          "bundled": true,
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@@ -1562,11 +1602,13 @@
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         "fs.realpath": {
           "version": "1.0.0",
-          "bundled": true
+          "bundled": true,
+          "optional": true
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         "fstream": {
           "version": "1.0.11",
           "bundled": true,
+          "optional": true,
           "requires": {
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@@ -1617,6 +1659,7 @@
         "glob": {
           "version": "7.1.2",
           "bundled": true,
+          "optional": true,
           "requires": {
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@@ -1628,7 +1671,8 @@
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+          "bundled": true,
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@@ -1652,6 +1696,7 @@
         "hawk": {
           "version": "3.1.3",
           "bundled": true,
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           "requires": {
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             "cryptiles": "2.0.5",
@@ -1661,7 +1706,8 @@
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         "hoek": {
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@@ -1676,6 +1722,7 @@
         "inflight": {
           "version": "1.0.6",
           "bundled": true,
+          "optional": true,
           "requires": {
             "once": "1.4.0",
             "wrappy": "1.0.2"
@@ -1683,7 +1730,8 @@
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         "inherits": {
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+          "bundled": true,
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@@ -1693,6 +1741,7 @@
         "is-fullwidth-code-point": {
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           "bundled": true,
+          "optional": true,
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@@ -1704,7 +1753,8 @@
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@@ -1767,11 +1817,13 @@
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         "mime-db": {
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-          "bundled": true
+          "bundled": true,
+          "optional": true
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           "version": "2.1.15",
           "bundled": true,
+          "optional": true,
           "requires": {
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@@ -1779,17 +1831,20 @@
         "minimatch": {
           "version": "3.0.4",
           "bundled": true,
+          "optional": true,
           "requires": {
             "brace-expansion": "1.1.7"
           }
         },
         "minimist": {
           "version": "0.0.8",
-          "bundled": true
+          "bundled": true,
+          "optional": true
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         "mkdirp": {
           "version": "0.5.1",
           "bundled": true,
+          "optional": true,
           "requires": {
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@@ -1839,7 +1894,8 @@
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+          "bundled": true,
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@@ -1854,6 +1910,7 @@
         "once": {
           "version": "1.4.0",
           "bundled": true,
+          "optional": true,
           "requires": {
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@@ -1879,7 +1936,8 @@
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@@ -1888,7 +1946,8 @@
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@@ -1921,6 +1980,7 @@
         "readable-stream": {
           "version": "2.2.9",
           "bundled": true,
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@@ -1963,13 +2023,15 @@
         "rimraf": {
           "version": "2.6.1",
           "bundled": true,
+          "optional": true,
           "requires": {
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@@ -1989,6 +2051,7 @@
         "sntp": {
           "version": "1.0.9",
           "bundled": true,
+          "optional": true,
           "requires": {
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@@ -2019,6 +2082,7 @@
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           "bundled": true,
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@@ -2028,6 +2092,7 @@
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           "bundled": true,
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@@ -2040,6 +2105,7 @@
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           "bundled": true,
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@@ -2052,6 +2118,7 @@
         "tar": {
           "version": "2.2.1",
           "bundled": true,
+          "optional": true,
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@@ -2101,7 +2168,8 @@
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@@ -2126,7 +2194,8 @@
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-          "bundled": true
+          "bundled": true,
+          "optional": true
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@@ -2223,6 +2292,19 @@
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       "dev": true
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+    "has-symbols": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/has-symbols/-/has-symbols-1.0.2.tgz",
+      "integrity": "sha512-chXa79rL/UC2KlX17jo3vRGz0azaWEx5tGqZg5pO3NUyEJVB17dMruQlzCCOfUvElghKcm5194+BCRvi2Rv/Gw=="
+    },
+    "has-tostringtag": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/has-tostringtag/-/has-tostringtag-1.0.0.tgz",
+      "integrity": "sha512-kFjcSNhnlGV1kyoGk7OXKSawH5JOb/LzUc5w9B02hOTO0dfFRjbHQKvg1d6cf3HbeUmtU9VbbV3qzZ2Teh97WQ==",
+      "requires": {
+        "has-symbols": "^1.0.2"
+      }
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       "resolved": "https://registry.npmjs.org/hoek/-/hoek-5.0.2.tgz",
@@ -2238,12 +2320,46 @@
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-      "resolved": "https://registry.npmjs.org/http-assert/-/http-assert-1.3.0.tgz",
-      "integrity": "sha1-oxpc+IyHPsu1eWkH1NbxMujAHko=",
+      "version": "1.5.0",
+      "resolved": "https://registry.npmjs.org/http-assert/-/http-assert-1.5.0.tgz",
+      "integrity": "sha512-uPpH7OKX4H25hBmU6G1jWNaqJGpTXxey+YOUizJUAgu0AjLUeC8D73hTrhvDS5D+GJN1DN1+hhc/eF/wpxtp0w==",
       "requires": {
-        "deep-equal": "1.0.1",
-        "http-errors": "1.6.2"
+        "deep-equal": "~1.0.1",
+        "http-errors": "~1.8.0"
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+          "resolved": "https://registry.npmjs.org/depd/-/depd-1.1.2.tgz",
+          "integrity": "sha1-m81S4UwJd2PnSbJ0xDRu0uVgtak="
+        },
+        "http-errors": {
+          "version": "1.8.0",
+          "resolved": "https://registry.npmjs.org/http-errors/-/http-errors-1.8.0.tgz",
+          "integrity": "sha512-4I8r0C5JDhT5VkvI47QktDW75rNlGVsUf/8hzjCC/wkWI/jdTRmBb9aI7erSG82r1bjKY3F6k28WnsVxB1C73A==",
+          "requires": {
+            "depd": "~1.1.2",
+            "inherits": "2.0.4",
+            "setprototypeof": "1.2.0",
+            "statuses": ">= 1.5.0 < 2",
+            "toidentifier": "1.0.0"
+          }
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+        "inherits": {
+          "version": "2.0.4",
+          "resolved": "https://registry.npmjs.org/inherits/-/inherits-2.0.4.tgz",
+          "integrity": "sha512-k/vGaX4/Yla3WzyMCvTQOXYeIHvqOKtnqBduzTHpzpQZzAskKMhZ2K+EnBiSM9zGSoIFeMpXKxa4dYeZIQqewQ=="
+        },
+        "setprototypeof": {
+          "version": "1.2.0",
+          "resolved": "https://registry.npmjs.org/setprototypeof/-/setprototypeof-1.2.0.tgz",
+          "integrity": "sha512-E5LDX7Wrp85Kil5bhZv46j8jOeboKq5JMmYM3gVGdGH8xFpPWXUMsNrlODCrkoxMEeNi/XZIwuRvY4XNwYMJpw=="
+        },
+        "statuses": {
+          "version": "1.5.0",
+          "resolved": "https://registry.npmjs.org/statuses/-/statuses-1.5.0.tgz",
+          "integrity": "sha1-Fhx9rBd2Wf2YEfQ3cfqZOBR4Yow="
+        }
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@@ -2359,9 +2475,12 @@
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-      "integrity": "sha1-nnFlPNFf/zQcecQVFGChMdMen8Q="
+      "version": "1.0.10",
+      "resolved": "https://registry.npmjs.org/is-generator-function/-/is-generator-function-1.0.10.tgz",
+      "integrity": "sha512-jsEjy9l3yiXEQ+PsXdmBwEPcOxaXWLspKdplFUVI9vq1iZgIekeC0L167qeu86czQaxed3q/Uzuw0swL0irL8A==",
+      "requires": {
+        "has-tostringtag": "^1.0.0"
+      }
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@@ -2483,9 +2602,12 @@
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-      "resolved": "https://registry.npmjs.org/keygrip/-/keygrip-1.0.2.tgz",
-      "integrity": "sha1-rTKXxVcGneqLz+ek+kkbdcXd65E="
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/keygrip/-/keygrip-1.1.0.tgz",
+      "integrity": "sha512-iYSchDJ+liQ8iwbSI2QqsQOvqv58eJCEanyJPJi+Khyu8smkcKSFUCbPwzFcL7YVtZ6eONjqRX/38caJ7QjRAQ==",
+      "requires": {
+        "tsscmp": "1.0.6"
+      }
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@@ -2496,34 +2618,87 @@
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-      "resolved": "https://registry.npmjs.org/koa/-/koa-2.4.1.tgz",
-      "integrity": "sha512-3caQ9OyLDYSL3wAhVfv2s9k3tLNgW18QxnKIPaRjzG9uXyDhp4tOo+U+XtbY+xbzEiCW5smjxMCegpZqCjmjMw==",
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-        "content-type": "1.0.4",
-        "cookies": "0.7.1",
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-        "escape-html": "1.0.3",
-        "fresh": "0.5.2",
-        "http-assert": "1.3.0",
-        "http-errors": "1.6.2",
-        "is-generator-function": "1.0.6",
-        "koa-compose": "4.0.0",
-        "koa-convert": "1.2.0",
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-        "on-finished": "2.3.0",
-        "only": "0.0.2",
-        "parseurl": "1.3.2",
-        "statuses": "1.4.0",
-        "type-is": "1.6.15",
-        "vary": "1.1.2"
+      "version": "2.13.3",
+      "resolved": "https://registry.npmjs.org/koa/-/koa-2.13.3.tgz",
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+          "resolved": "https://registry.npmjs.org/setprototypeof/-/setprototypeof-1.2.0.tgz",
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+        "statuses": {
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+          "resolved": "https://registry.npmjs.org/statuses/-/statuses-1.5.0.tgz",
+          "integrity": "sha1-Fhx9rBd2Wf2YEfQ3cfqZOBR4Yow="
+        }
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@@ -2563,27 +2738,17 @@
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-      "integrity": "sha1-KAClE9nDYe8NY4UrA45Pby1adzw="
+      "version": "4.1.0",
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-      "integrity": "sha1-2kCHXfSd4FOQmNFwC1CCDOvNIdA=",
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/koa-convert/-/koa-convert-2.0.0.tgz",
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-          "integrity": "sha1-qFzLQLfZhtjlo0Wzoazo6rz1Tec=",
-          "requires": {
-            "any-promise": "1.3.0"
-          }
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+        "co": "^4.6.0",
+        "koa-compose": "^4.1.0"
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@@ -2851,16 +3016,16 @@
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-      "resolved": "https://registry.npmjs.org/mime-db/-/mime-db-1.30.0.tgz",
-      "integrity": "sha1-dMZD2i3Z1qRTmZY0ZbJtXKfXHwE="
+      "version": "1.50.0",
+      "resolved": "https://registry.npmjs.org/mime-db/-/mime-db-1.50.0.tgz",
+      "integrity": "sha512-9tMZCDlYHqeERXEHO9f/hKfNXhre5dK2eE/krIvUjZbS2KPcqGDfNShIWS1uW9XOTKQKqK6qbeOci18rbfW77A=="
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-      "resolved": "https://registry.npmjs.org/mime-types/-/mime-types-2.1.17.tgz",
-      "integrity": "sha1-Cdejk/A+mVp5+K+Fe3Cp4KsWVXo=",
+      "version": "2.1.33",
+      "resolved": "https://registry.npmjs.org/mime-types/-/mime-types-2.1.33.tgz",
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       "requires": {
-        "mime-db": "1.30.0"
+        "mime-db": "1.50.0"
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@@ -2906,9 +3071,9 @@
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-      "resolved": "https://registry.npmjs.org/negotiator/-/negotiator-0.6.1.tgz",
-      "integrity": "sha1-KzJxhOiZIQEXeyhWP7XnECrNDKk="
+      "version": "0.6.2",
+      "resolved": "https://registry.npmjs.org/negotiator/-/negotiator-0.6.2.tgz",
+      "integrity": "sha512-hZXc7K2e+PgeI1eDBe/10Ard4ekbfrrqG8Ep+8Jmf4JID2bNg7NvCPOZN+kfF574pFQI7mum2AUqDidoKqcTOw=="
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@@ -3111,9 +3276,9 @@
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-      "resolved": "https://registry.npmjs.org/parseurl/-/parseurl-1.3.2.tgz",
-      "integrity": "sha1-/CidTtiZMRlGDBViUyYs3I3mW/M="
+      "version": "1.3.3",
+      "resolved": "https://registry.npmjs.org/parseurl/-/parseurl-1.3.3.tgz",
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@@ -3697,6 +3862,11 @@
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       "integrity": "sha1-uDVx+k2MJbguIxsG46MFXeTKGkc="
     },
+    "toidentifier": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/toidentifier/-/toidentifier-1.0.0.tgz",
+      "integrity": "sha512-yaOH/Pk/VEhBWWTlhI+qXxDFXlejDGcQipMlyxda9nthulaxLZUNcUqFxokp0vcYnvteJln5FNQDRrxj3YcbVw=="
+    },
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       "resolved": "https://registry.npmjs.org/touch/-/touch-3.1.0.tgz",
@@ -3716,13 +3886,18 @@
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       "integrity": "sha1-qf2LA5Swro//guBjOgo2zK1bX4Y="
     },
+    "tsscmp": {
+      "version": "1.0.6",
+      "resolved": "https://registry.npmjs.org/tsscmp/-/tsscmp-1.0.6.tgz",
+      "integrity": "sha512-LxhtAkPDTkVCMQjt2h6eBVY28KCjikZqZfMcC15YBeNjkgUpdCfBu5HoiOTDu86v6smE8yOjyEktJ8hlbANHQA=="
+    },
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-      "resolved": "https://registry.npmjs.org/type-is/-/type-is-1.6.15.tgz",
-      "integrity": "sha1-yrEPtJCeRByChC6v4a1kbIGARBA=",
+      "version": "1.6.18",
+      "resolved": "https://registry.npmjs.org/type-is/-/type-is-1.6.18.tgz",
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       "requires": {
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-        "mime-types": "2.1.17"
+        "mime-types": "~2.1.24"
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@@ -3987,6 +4162,11 @@
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       "integrity": "sha1-HBH5IY8HYImkfdUS+TxmmaaoHVI=",
       "dev": true
+    },
+    "ylru": {
+      "version": "1.2.1",
+      "resolved": "https://registry.npmjs.org/ylru/-/ylru-1.2.1.tgz",
+      "integrity": "sha512-faQrqNMzcPCHGVC2aaOINk13K+aaBDUPjGWl0teOXywElLjyVAB6Oe2jj62jHYtwsU49jXhScYbvPENK+6zAvQ=="
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 }
diff --git a/package.json b/package.json
index 330c3a9..f260d8f 100644
--- a/package.json
+++ b/package.json
@@ -18,7 +18,7 @@
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     "boom": "^6.0.0",
     "dotenv": "^4.0.0",
-    "koa": "^2.3.0",
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     "koa-better-error-handler": "^1.3.0",
     "koa-json": "^2.0.2",
     "koa-logger": "^3.1.0",