diff --git a/Gemfile.lock b/Gemfile.lock
index 6a05bfc..2c69d38 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -67,7 +67,7 @@ GEM
     case_transform (0.2)
       activesupport
     coderay (1.1.2)
-    concurrent-ruby (1.0.5)
+    concurrent-ruby (1.1.6)
     crass (1.0.3)
     cucumber (3.1.0)
       builder (>= 2.1.2)
@@ -141,7 +141,7 @@ GEM
       mini_portile2 (~> 2.3.0)
     public_suffix (3.0.2)
     puma (3.11.3)
-    rack (2.0.4)
+    rack (2.2.2)
     rack-contrib (2.0.1)
       rack (~> 2.0)
     rack-cors (1.0.2)
@@ -188,7 +188,7 @@ GEM
     spring-watcher-listen (2.0.1)
       listen (>= 2.7, < 4.0)
       spring (>= 1.2, < 3.0)
-    sprockets (3.7.1)
+    sprockets (4.0.0)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
     sprockets-rails (3.2.1)