Update gem "rubocop"

Gemfile

@@ -116,11 +116,15 @@ group :development, :test do
 
   # Automatic Ruby code style checking tool.
   # Aims to enforce the community-driven Ruby Style Guide.
-  gem 'rubocop', '~> 0.67.2'
+  gem 'rubocop', '~> 0.72.0'
 
   # A collection of RuboCop cops
   # to check for performance optimizations in Ruby code.
-  gem 'rubocop-performance', '~> 1.1'
+  gem 'rubocop-performance', '~> 1.4'
+
+  # Automatic Rails code style checking tool. A RuboCop extension
+  # focused on enforcing Rails best practices and coding conventions.
+  gem 'rubocop-rails', '~> 2.2'
 
   # rspec-rails is a testing framework for Rails 3+
   gem 'rspec-rails', '~> 3.8'

Gemfile.lock

@@ -256,7 +256,6 @@ GEM
       yard (~> 0.9.11)
     pry-rails (0.3.9)
       pry (>= 0.10.4)
-    psych (3.1.0)
     public_suffix (3.1.1)
     puma (4.0.0)
       nio4r (~> 2.0)
@@ -339,16 +338,18 @@ GEM
       rspec-mocks (~> 3.8.0)
       rspec-support (~> 3.8.0)
     rspec-support (3.8.2)
-    rubocop (0.67.2)
+    rubocop (0.72.0)
       jaro_winkler (~> 1.5.1)
       parallel (~> 1.10)
-      parser (>= 2.5, != 2.5.1.1)
-      psych (>= 3.1.0)
+      parser (>= 2.6)
       rainbow (>= 2.2.2, < 4.0)
       ruby-progressbar (~> 1.7)
-      unicode-display_width (>= 1.4.0, < 1.6)
-    rubocop-performance (1.1.0)
-      rubocop (>= 0.67.0)
+      unicode-display_width (>= 1.4.0, < 1.7)
+    rubocop-performance (1.4.0)
+      rubocop (>= 0.71.0)
+    rubocop-rails (2.2.0)
+      rack (>= 1.1)
+      rubocop (>= 0.72.0)
     ruby-graphviz (1.2.4)
     ruby-progressbar (1.10.1)
     ruby_dep (1.5.0)
@@ -488,8 +489,9 @@ DEPENDENCIES
   rest-client (~> 2.0)
   rolify (~> 5.2)
   rspec-rails (~> 3.8)
-  rubocop (~> 0.67.2)
-  rubocop-performance (~> 1.1)
+  rubocop (~> 0.72.0)
+  rubocop-performance (~> 1.4)
+  rubocop-rails (~> 2.2)
   selenium-webdriver (~> 3.14)
   sentry-raven
   shoulda-matchers (= 4.0.0.rc1)