diff --git a/Gemfile.lock b/Gemfile.lock
index 52efcdb..05927bd 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -45,6 +45,7 @@ GEM
       tzinfo (~> 1.1)
     arel (6.0.2)
     builder (3.2.2)
+    concurrent-ruby (1.1.5)
     diff-lcs (1.2.5)
     docile (1.1.5)
     erubis (2.7.0)
@@ -62,7 +63,7 @@ GEM
     minitest (5.7.0)
     nokogiri (1.6.6.2)
       mini_portile (~> 0.6.0)
-    rack (1.6.4)
+    rack (1.6.12)
     rack-test (0.6.3)
       rack (>= 1.0)
     rails (4.2.3)
@@ -111,8 +112,9 @@ GEM
     simplecov-html (0.10.0)
     simplecov-rcov (0.2.3)
       simplecov (>= 0.4.1)
-    sprockets (3.2.0)
-      rack (~> 1.0)
+    sprockets (3.7.2)
+      concurrent-ruby (~> 1.0)
+      rack (> 1, < 3)
     sprockets-rails (2.3.2)
       actionpack (>= 3.0)
       activesupport (>= 3.0)