diff --git a/Gemfile.lock b/Gemfile.lock
index 710310b..f0e6858 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -26,7 +26,7 @@ GEM
       sass (>= 3.3.0, < 3.5)
     compass-import-once (1.0.5)
       sass (>= 3.2, < 3.5)
-    concurrent-ruby (1.0.5)
+    concurrent-ruby (1.1.7)
     contracts (0.13.0)
     dotenv (2.2.1)
     em-websocket (0.5.1)
@@ -104,7 +104,7 @@ GEM
       activesupport (>= 3.1)
     parallel (1.12.1)
     public_suffix (3.0.2)
-    rack (2.0.4)
+    rack (2.2.3)
     rack-livereload (0.3.16)
       rack
     rb-fsevent (0.10.3)
@@ -115,7 +115,7 @@ GEM
     slim (3.0.9)
       temple (>= 0.7.6, < 0.9)
       tilt (>= 1.3.3, < 2.1)
-    sprockets (3.7.1)
+    sprockets (4.0.2)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
     temple (0.8.0)