diff --git a/Gemfile.lock b/Gemfile.lock
index fa1b761..53e75b9 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -52,6 +52,7 @@ GEM
       coffee-script-source
       execjs
     coffee-script-source (1.10.0)
+    concurrent-ruby (1.1.7)
     connection_pool (2.2.0)
     debug_inspector (0.0.2)
     erubis (2.7.0)
@@ -78,7 +79,7 @@ GEM
     nokogiri (1.6.6.4)
       mini_portile (~> 0.6.0)
     pg (0.18.4)
-    rack (1.6.4)
+    rack (1.6.13)
     rack-test (0.6.3)
       rack (>= 1.0)
     rails (4.2.5)
@@ -125,7 +126,8 @@ GEM
       json (~> 1.7, >= 1.7.7)
       rdoc (~> 4.0)
     spring (1.4.4)
-    sprockets (3.4.0)
+    sprockets (3.7.2)
+      concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
     sprockets-rails (2.3.3)
       actionpack (>= 3.0)