Add rubocop

Gemfile

@@ -68,6 +68,7 @@ group :development do
   # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
   gem 'bullet'
   gem 'nested_scaffold'
+  gem 'rubocop', require: false
   gem 'seed_dump'
   gem 'spring'
   gem 'spring-watcher-listen', '~> 2.0.0'

Gemfile.lock

@@ -73,6 +73,7 @@ GEM
       zeitwerk (~> 2.3)
     addressable (2.8.0)
       public_suffix (>= 2.0.2, < 5.0)
+    ast (2.4.2)
     bcrypt (3.1.16)
     bindex (0.8.1)
     bootsnap (1.9.1)
@@ -153,8 +154,6 @@ GEM
     nested_scaffold (1.1.0)
     newrelic_rpm (8.0.0)
     nio4r (2.5.8)
-    nokogiri (1.12.5-x86_64-darwin)
-      racc (~> 1.4)
     nokogiri (1.12.5-x86_64-linux)
       racc (~> 1.4)
     omniauth (2.0.4)
@@ -162,6 +161,9 @@ GEM
       rack (>= 1.6.2, < 3)
       rack-protection
     orm_adapter (0.5.0)
+    parallel (1.21.0)
+    parser (3.1.0.0)
+      ast (~> 2.4.1)
     pg (1.2.3)
     public_suffix (4.0.6)
     puma (5.5.2)
@@ -202,6 +204,7 @@ GEM
       method_source
       rake (>= 0.13)
       thor (~> 1.0)
+    rainbow (3.1.1)
     rake (13.0.6)
     rb-fsevent (0.11.0)
     rb-inotify (0.10.1)
@@ -210,6 +213,7 @@ GEM
     responders (3.0.1)
       actionpack (>= 5.0)
       railties (>= 5.0)
+    rexml (3.2.5)
     rspec-core (3.10.1)
       rspec-support (~> 3.10.0)
     rspec-expectations (3.10.1)
@@ -227,6 +231,18 @@ GEM
       rspec-mocks (~> 3.10)
       rspec-support (~> 3.10)
     rspec-support (3.10.2)
+    rubocop (1.24.1)
+      parallel (~> 1.10)
+      parser (>= 3.0.0.0)
+      rainbow (>= 2.2.2, < 4.0)
+      regexp_parser (>= 1.8, < 3.0)
+      rexml
+      rubocop-ast (>= 1.15.1, < 2.0)
+      ruby-progressbar (~> 1.7)
+      unicode-display_width (>= 1.4.0, < 3.0)
+    rubocop-ast (1.15.1)
+      parser (>= 3.0.1.1)
+    ruby-progressbar (1.11.0)
     sassc (2.4.0)
       ffi (~> 1.9)
     sassc-rails (2.1.2)
@@ -264,6 +280,7 @@ GEM
       concurrent-ruby (~> 1.0)
     uglifier (4.2.0)
       execjs (>= 0.3.0, < 3)
+    unicode-display_width (2.1.0)
     uniform_notifier (1.14.2)
     warden (1.2.9)
       rack (>= 2.0.9)
@@ -310,6 +327,7 @@ DEPENDENCIES
   rails (~> 6.1.4.1)
   rails-controller-testing
   rspec-rails (~> 4.1.2)
+  rubocop
   sassc-rails
   seed_dump
   spring