diff --git a/Gemfile.lock b/Gemfile.lock
index f447aa0..ccd9339 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -17,8 +17,10 @@ GEM
       thread_safe (~> 0.3, >= 0.3.4)
       tzinfo (~> 1.1)
     builder (3.2.2)
+    concurrent-ruby (1.1.10)
     diff-lcs (1.2.5)
-    i18n (0.7.0)
+    i18n (0.9.5)
+      concurrent-ruby (~> 1.0)
     json (1.8.3)
     minitest (5.9.1)
     rake (12.3.0)