Enable Ruby linting

* Add Rubocop
* Add guard-rubocop
* Enable Ruby linting on Hound

.hound.yml

@@ -3,6 +3,7 @@ java_script:
   config_file: config/.jshint.json
   ignore_file: config/.jshint_ignore
 ruby:
-  enabled: false
+  enabled: true
+  config_file: .rubocop.yml
 scss:
   enabled: false

.rubocop.yml

+AllCops:
+  RunRailsCops: true
+
+# Commonly used screens these days easily fit more than 80 characters.
+Metrics/LineLength:
+  Max: 120
+
+# Too short methods lead to extraction of single-use methods, which can make
+# the code easier to read (by naming things), but can also clutter the class
+Metrics/MethodLength: 
+  Max: 20
+
+# The guiding principle of classes is SRP, SRP can't be accurately measured by LoC
+Metrics/ClassLength:
+  Max: 1500
+
+# No space makes the method definition shorter and differentiates
+# from a regular assignment.
+Style/SpaceAroundEqualsInParameterDefault:
+  EnforcedStyle: no_space
+
+# Single quotes being faster is hardly measurable and only affects parse time.
+# Enforcing double quotes reduces the times where you need to change them
+# when introducing an interpolation. Use single quotes only if their semantics
+# are needed.
+Style/StringLiterals:
+  EnforcedStyle: double_quotes
+
+# We do not need to support Ruby 1.9, so this is good to use.
+Style/SymbolArray:
+  Enabled: true
+
+# Most readable form.
+Style/AlignHash:
+  EnforcedHashRocketStyle: table
+  EnforcedColonStyle: table
+
+# Mixing the styles looks just silly.
+# REVIEW: Enable once https://github.com/bbatsov/rubocop/commit/760ce1ed2cf10beda5e163f934c03a6fb6daa38e
+#   is released.
+#Style/HashSyntax:
+#  EnforcedStyle: ruby19_no_mixed_keys
+
+# has_key? and has_value? are far more readable than key? and value?
+Style/DeprecatedHashMethods:
+  Enabled: false
+
+# String#% is by far the least verbose and only object oriented variant.
+Style/FormatString:
+  EnforcedStyle: percent
+
+Style/CollectionMethods:
+  Enabled: true
+  PreferredMethods:
+    # inject seems more common in the community.
+    reduce: "inject"
+
+
+# Either allow this style or don't. Marking it as safe with parenthesis
+# is silly. Let's try to live without them for now.
+Style/ParenthesesAroundCondition:
+  AllowSafeAssignment: false
+Lint/AssignmentInCondition:
+  AllowSafeAssignment: false
+
+# A specialized exception class will take one or more arguments and construct the message from it.
+# So both variants make sense. 
+Style/RaiseArgs:
+  Enabled: false
+
+# Fail is an alias of raise. Avoid aliases, it's more cognitive load for no gain.
+# The argument that fail should be used to abort the program is wrong too,
+# there's Kernel#abort for that.
+Style/SignalException:
+  EnforcedStyle: only_raise
+
+# Suppressing exceptions can be perfectly fine, and be it to avoid to
+# explicitly type nil into the rescue since that's what you want to return,
+# or suppressing LoadError for optional dependencies
+Lint/HandleExceptions:
+  Enabled: false
+
+Style/SpaceInsideBlockBraces:
+  # The space here provides no real gain in readability while consuming
+  # horizontal space that could be used for a better parameter name.
+  # Also {| differentiates better from a hash than { | does.
+  SpaceBeforeBlockParameters: false
+
+# No trailing space differentiates better from the block:
+# foo} means hash, foo } means block.
+Style/SpaceInsideHashLiteralBraces:
+  EnforcedStyle: no_space
+
+# { ... } for multi-line blocks is okay, follow Weirichs rule instead:
+# https://web.archive.org/web/20140221124509/http://onestepback.org/index.cgi/Tech/Ruby/BraceVsDoEnd.rdoc
+Style/Blocks:
+  Enabled: false
+
+# do / end blocks should be used for side effects,
+# methods that run a block for side effects and have
+# a useful return value are rare, assign the return
+# value to a local variable for those cases.
+Style/MethodCalledOnDoEndBlock:
+  Enabled: true
+
+# Enforcing the names of variables? To single letter ones? Just no.
+Style/SingleLineBlockParams:
+  Enabled: false
+
+# Shadowing outer local variables with block parameters is often useful
+# to not reinvent a new name for the same thing, it highlights the relation
+# between the outer variable and the parameter. The cases where it's actually
+# confusing are rare, and usually bad for other reasons already, for example
+# because the method is too long.
+Lint/ShadowingOuterLocalVariable:
+  Enabled: false
+
+# Check with yard instead.
+Style/Documentation:
+  Enabled: false 
+
+# This is just silly. Calling the argument `other` in all cases makes no sense.
+Style/OpMethod:
+  Enabled: false 
+
+# There are valid cases, for example debugging Cucumber steps,
+# also they'll fail CI anyway
+Lint/Debugger:
+  Enabled: false
+

Gemfile

@@ -216,12 +216,14 @@ group :development do
   # Automatic test runs
   gem 'guard-cucumber', '1.5.3'
   gem 'guard-rspec',    '4.5.0'
+  gem 'guard-rubocop',  '1.2.0'
   gem 'guard',          '2.12.4', :require => false
   gem 'rb-fsevent',     '0.9.4', :require => false
   gem 'rb-inotify',     '0.9.5', :require => false
 
   # Linters
-  gem 'jshint', '1.3.1'
+  gem 'jshint',  '1.3.1'
+  gem 'rubocop', '0.29.1'
 
   # Preloading environment
 

Gemfile.lock

@@ -62,6 +62,9 @@ GEM
       activemodel
       fog (>= 1.8.0)
       unf
+    ast (2.0.0)
+    astrolabe (1.3.0)
+      parser (>= 2.2.0.pre.3, < 3.0)
     autoprefixer-rails (5.1.7)
       execjs
       json
@@ -318,6 +321,9 @@ GEM
       guard (~> 2.1)
       guard-compat (~> 1.1)
       rspec (>= 2.99.0, < 4.0)
+    guard-rubocop (1.2.0)
+      guard (~> 2.0)
+      rubocop (~> 0.20)
     haml (4.0.6)
       tilt
     handlebars_assets (0.20.1)
@@ -439,7 +445,10 @@ GEM
       faraday (~> 0.9.0)
       nokogiri (~> 1.6)
     orm_adapter (0.5.0)
+    parser (2.2.0.3)
+      ast (>= 1.1, < 3.0)
     phantomjs (1.9.8.0)
+    powerpack (0.1.0)
     pry (0.10.1)
       coderay (~> 1.1.0)
       method_source (~> 0.8.1)
@@ -547,6 +556,7 @@ GEM
       activesupport (= 4.2.0)
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
+    rainbow (2.0.0)
     raindrops (0.13.0)
     rake (10.4.2)
     rb-fsevent (0.9.4)
@@ -586,6 +596,12 @@ GEM
       rspec-mocks (~> 3.1.0)
       rspec-support (~> 3.1.0)
     rspec-support (3.1.2)
+    rubocop (0.29.1)
+      astrolabe (~> 1.3)
+      parser (>= 2.2.0.1, < 3.0)
+      powerpack (~> 0.1)
+      rainbow (>= 1.99.1, < 3.0)
+      ruby-progressbar (~> 1.4)
     ruby-oembed (0.8.12)
     ruby-progressbar (1.7.1)
     rubyzip (1.1.7)
@@ -721,6 +737,7 @@ DEPENDENCIES
   guard (= 2.12.4)
   guard-cucumber (= 1.5.3)
   guard-rspec (= 4.5.0)
+  guard-rubocop (= 1.2.0)
   haml (= 4.0.6)
   handlebars_assets (= 0.20.1)
   http_accept_language (= 2.0.5)
@@ -782,6 +799,7 @@ DEPENDENCIES
   roxml (= 3.1.6)
   rspec-instafail (= 0.2.6)
   rspec-rails (= 3.1.0)
+  rubocop (= 0.29.1)
   ruby-oembed (= 0.8.12)
   sass-rails (= 5.0.1)
   selenium-webdriver (= 2.45.0)

Guardfile

-guard :rspec, cmd: 'bin/spring rspec', all_on_start: false, all_after_pass: false do
-  watch(%r{^spec/.+_spec\.rb$})
-  watch(%r{^lib/(.+)\.rb$})     { |m| "spec/lib/#{m[1]}_spec.rb" }
-  watch('spec/spec_helper.rb')  { "spec" }
+guard :rspec, cmd: "bin/spring rspec", all_on_start: false, all_after_pass: false do
+  watch(/^spec\/.+_spec\.rb$/)
+  watch(/^lib\/(.+)\.rb$/)       {|m| "spec/lib/#{m[1]}_spec.rb" }
+  watch(/spec\/spec_helper.rb/)  { "spec" }
 
   # Rails example
-  watch(%r{^spec/.+_spec\.rb$})
-  watch(%r{^app/(.+)\.rb$})                           { |m| "spec/#{m[1]}_spec.rb" }
-  watch(%r{^lib/(.+)\.rb$})                           { |m| "spec/lib/#{m[1]}_spec.rb" }
-  watch(%r{^app/controllers/(.+)_(controller)\.rb$})  { |m| ["spec/routing/#{m[1]}_routing_spec.rb", "spec/#{m[2]}s/#{m[1]}_#{m[2]}_spec.rb", "spec/acceptance/#{m[1]}_spec.rb"] }
+  watch(/^spec\/.+_spec\.rb$/)
+  watch(/^app\/(.+)\.rb$/)                            {|m| "spec/#{m[1]}_spec.rb" }
+  watch(/^lib\/(.+)\.rb$/)                            {|m| "spec/lib/#{m[1]}_spec.rb" }
+  watch(%r{^app/controllers/(.+)_(controller)\.rb$}) {|m|
+    ["spec/routing/#{m[1]}_routing_spec.rb",
+     "spec/#{m[2]}s/#{m[1]}_#{m[2]}_spec.rb",
+     "spec/acceptance/#{m[1]}_spec.rb"]
+  }
   watch(%r{^spec/support/(.+)\.rb$})                  { "spec" }
-  watch('spec/spec_helper.rb')                        { "spec" }
-  watch('config/routes.rb')                           { "spec/routing" }
-  watch('app/controllers/application_controller.rb')  { "spec/controllers" }
+  watch("spec/spec_helper.rb")                        { "spec" }
+  watch("config/routes.rb")                           { "spec/routing" }
+  watch("app/controllers/application_controller.rb")  { "spec/controllers" }
 
   # Capybara request specs
-  watch(%r{^app/views/(.+)/.*\.(erb|haml)$})          { |m| "spec/requests/#{m[1]}_spec.rb" }
+  watch(%r{^app/views/(.+)/.*\.(erb|haml)$})          {|m| "spec/requests/#{m[1]}_spec.rb" }
 end
 
-guard :cucumber, command_prefix: 'bin/spring', bundler: false, all_on_start: false, all_after_pass: false do
-  watch(%r{^features/.+\.feature$})
-  watch(%r{^features/support/.+$})          { 'features' }
-  watch(%r{^features/step_definitions/(.+)_steps\.rb$}) { |m| Dir[File.join("**/#{m[1]}.feature")][0] || 'features' }
+guard(:cucumber,
+      command_prefix: "bin/spring",
+      bundler:        false,
+      all_on_start:   false,
+      all_after_pass: false) do
+  watch(/^features\/.+\.feature$/)
+  watch(%r{^features/support/.+$})          { "features" }
+  watch(%r{^features/step_definitions/(.+)_steps\.rb$}) {|m|
+    Dir[File.join("**/#{m[1]}.feature")][0] || "features"
+  }
+end
+
+guard :rubocop, all_on_start: false, keep_failed: false do
+  watch(/(?:app|config|db|lib|features|spec)\/.+\.rb$/)
+  watch(/(config.ru|Gemfile|Guardfile|Rakefile)$/)
 end