diff --git a/Gemfile.lock b/Gemfile.lock
index 0ac2ad8..c28b374 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -6,7 +6,7 @@ GEM
     albino (1.3.3)
       posix-spawn (>= 0.3.6)
     colorator (1.1.0)
-    concurrent-ruby (1.1.4)
+    concurrent-ruby (1.3.7)
     em-websocket (0.5.1)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0.6.0)