diff --git a/Gemfile b/Gemfile
index 5bc2a80..70cdf73 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,4 +1,4 @@
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
 # Specify your gem's dependencies in slugtastic.gemspec
 gemspec
diff --git a/Gemfile.lock b/Gemfile.lock
index 07186d4..31c92b0 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -6,39 +6,44 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
-    activemodel (3.0.20)
-      activesupport (= 3.0.20)
-      builder (~> 2.1.2)
-      i18n (~> 0.5.0)
-    activesupport (3.0.20)
-    builder (2.1.2)
-    diff-lcs (1.2.5)
-    i18n (0.5.4)
-    rake (11.1.1)
-    rspec (3.4.0)
-      rspec-core (~> 3.4.0)
-      rspec-expectations (~> 3.4.0)
-      rspec-mocks (~> 3.4.0)
-    rspec-core (3.4.4)
-      rspec-support (~> 3.4.0)
-    rspec-expectations (3.4.0)
+    activemodel (5.2.0)
+      activesupport (= 5.2.0)
+    activesupport (5.2.0)
+      concurrent-ruby (~> 1.0, >= 1.0.2)
+      i18n (>= 0.7, < 2)
+      minitest (~> 5.1)
+      tzinfo (~> 1.1)
+    concurrent-ruby (1.0.5)
+    diff-lcs (1.3)
+    i18n (1.0.1)
+      concurrent-ruby (~> 1.0)
+    minitest (5.11.3)
+    rake (12.3.1)
+    rspec (3.7.0)
+      rspec-core (~> 3.7.0)
+      rspec-expectations (~> 3.7.0)
+      rspec-mocks (~> 3.7.0)
+    rspec-core (3.7.1)
+      rspec-support (~> 3.7.0)
+    rspec-expectations (3.7.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.4.0)
-    rspec-mocks (3.4.1)
+      rspec-support (~> 3.7.0)
+    rspec-mocks (3.7.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.4.0)
-    rspec-support (3.4.1)
-    supermodel (0.1.6)
-      activemodel (~> 3.0.0)
+      rspec-support (~> 3.7.0)
+    rspec-support (3.7.1)
+    thread_safe (0.3.6)
+    tzinfo (1.2.5)
+      thread_safe (~> 0.1)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  rake (~> 11.1)
-  rspec (~> 3.4)
+  activemodel (~> 5)
+  rake (~> 12.3)
+  rspec (~> 3.7)
   slugtastic!
-  supermodel (~> 0)
 
 BUNDLED WITH
-   1.11.2
+   1.16.1