diff --git a/Gemfile.lock b/Gemfile.lock
index 077e309..07077f0 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -65,7 +65,7 @@ GEM
     minitest (5.8.4)
     nokogiri (1.6.7.2)
       mini_portile2 (~> 2.0.0.rc2)
-    rack (1.6.4)
+    rack (1.6.13)
     rack-cors (0.4.0)
     rack-test (0.6.3)
       rack (>= 1.0)