Added example file upload script

refs https://github.com/TryGhost/Toolbox/issues/219

- Example on how to use the "files.upload" method exposed through Admin API SDK / Admin API.

Author: naz

upload-file.js

@@ -0,0 +1,34 @@
+/**
+ * Warning: This script uses an experimental alpha feature
+ *
+ * Upload a local media file
+ *
+ * To run me:
+ *
+ * 1. Replace "YOUR_ADMIN_API_KEY" below with your admin key (and edit the URL if you're not using localhost)
+ * 2. Make sure the example you want to test is uncommented
+ * 3. Run `node upload-file.js ./sample_document.pdf some-ID-123`
+ *              ^ script name   ^ path to file     ^ reference
+ */
+
+// The admin API client is the easiest way to use the API
+const GhostAdminAPI = require('@tryghost/admin-api');
+const path = require('path');
+
+// Configure the client
+const api = new GhostAdminAPI({
+    url: 'http://localhost:2368',
+    // @TODO: edit your key here
+    key: 'YOUR_ADMIN_API_KEY_HERE',
+    version: 'canary'
+});
+
+const file = process.argv[2];
+const ref = process.argv[3];
+
+api.files.upload({
+    file: path.join(__dirname, file),
+    ref
+})
+    .then(response => console.log(response))
+    .catch(error => console.error(error));