diff --git a/Gemfile.lock b/Gemfile.lock
index faaa9f3..6daae68 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -46,6 +46,7 @@ GEM
     bcp47 (0.3.3)
       i18n
     builder (3.2.2)
+    concurrent-ruby (1.1.10)
     deprecation (0.2.2)
       activesupport
     diff-lcs (1.2.5)
@@ -66,7 +67,8 @@ GEM
     htmlentities (4.3.4)
     http-cookie (1.0.2)
       domain_name (~> 0.5)
-    i18n (0.7.0)
+    i18n (0.9.5)
+      concurrent-ruby (~> 1.0)
     iso-639 (0.2.5)
     json (1.8.5)
     json-ld (1.99.0)