diff --git a/Gemfile.lock b/Gemfile.lock
index e7cb44b..17cd2b3 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -153,7 +153,7 @@ GEM
       regexp_parser (>= 1.5, < 3.0)
       xpath (~> 3.2)
     chunky_png (1.4.0)
-    concurrent-ruby (1.3.5)
+    concurrent-ruby (1.3.7)
     connection_pool (2.5.5)
     crack (1.0.0)
       bigdecimal