diff --git a/Gemfile.lock b/Gemfile.lock
index 6b18067..37a3062 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -48,7 +48,7 @@ GEM
       rack (>= 1.2, < 3)
     pkg-config (1.1.7)
     power_assert (0.3.0)
-    rack (1.6.4)
+    rack (1.6.12)
     rake (11.2.2)
     rdoc (4.2.2)
       json (~> 1.4)