diff --git a/Gemfile.lock b/Gemfile.lock
index 909f863..e506939 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -70,7 +70,7 @@ GEM
     pg (0.17.1)
     polyamorous (1.1.0)
       activerecord (>= 3.0)
-    rack (1.5.2)
+    rack (1.5.5)
     rack-test (0.6.2)
       rack (>= 1.0)
     rails (4.1.7)