diff --git a/Gemfile.lock b/Gemfile.lock
index 086a63b1f9a96821eca379bbeeb9114c1f658eb7..8c0f0e73e4d00ed63373dc2f2b5274f86c4928d5 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -37,7 +37,7 @@ GEM
     netrc (0.11.0)
     peach (0.5.1)
     public_suffix (3.1.1)
-    rack (2.0.7)
+    rack (1.6.4)
     rack-cache (1.9.0)
       rack (>= 0.4)
     rb-readline (0.5.5)