diff --git a/Gemfile.lock b/Gemfile.lock
index 9566632..829b545 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -28,7 +28,7 @@ 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 (1.1.6)
     contracts (0.13.0)
     dotenv (2.2.1)
     em-websocket (0.5.1)
@@ -49,7 +49,7 @@ GEM
     http_parser.rb (0.6.0)
     i18n (0.7.0)
     kramdown (1.15.0)
-    libv8 (3.16.14.19-x86_64-linux)
+    libv8 (3.16.14.19)
     listen (3.0.8)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
@@ -111,7 +111,7 @@ GEM
     parallel (1.12.0)
     public_suffix (3.0.0)
     puma (3.10.0)
-    rack (1.6.8)
+    rack (1.6.13)
     rack-contrib (1.6.0)
       rack (~> 1.4)
     rack-livereload (0.3.16)
@@ -126,7 +126,7 @@ GEM
       rake (>= 0.9, < 13)
       sass (~> 3.4.20)
     servolux (0.13.0)
-    sprockets (3.7.1)
+    sprockets (4.0.2)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
     temple (0.8.0)