Get useful feedback from Rubocop Metrics cops

One of the biggest pros of linters like Rubocop is to get valuable feedback to
help write better code. The way we have Rubocop configured now we don't prevent
new code from adhere improved code quality and this is specially important when
touching code that already suffers from complexity.

Without all Rubocop's Metrics cops enabled there's no way to get this insights
and write better code. This enables them while regenerating the
`.rubocop_todo.yml` to hide the current violations.

So, next time we touch existing code that we think could be simpler, we should
go to `.rubocop_todo.yml` and remove any occurrences of the file in question.
This way we could Rubocop's feedback right in the editor. This is tremendously
helpful when refactoring. It shows you where to start.

.codeclimate.yml

@@ -2,7 +2,7 @@ version: "2"
 plugins:
   rubocop:
     enabled: true
-    channel: "rubocop-0-55"
+    channel: "rubocop-0-57"
   scss-lint:
     enabled: true
     checks:
@@ -19,23 +19,23 @@ checks:
   argument-count:
     enabled: false
   complex-logic:
-    enabled: true
+    enabled: false
   file-lines:
-    enabled: true
+    enabled: false
   method-complexity:
-    enabled: true
+    enabled: false
   method-count:
     enabled: false
   method-lines:
     enabled: false
   nested-control-flow:
-    enabled: true
+    enabled: false
   return-statements:
-    enabled: true
+    enabled: false
   similar-code:
-    enabled: true
+    enabled: false
   identical-code:
-    enabled: true
+    enabled: false
 exclude_patterns:
 - "spec/**/*"
 - "vendor/**/*"

.rubocop.yml

@@ -4,16 +4,12 @@ inherit_from:
 AllCops:
   TargetRubyVersion: 2.1
   TargetRailsVersion: 3.2
-  Include:
-    - '**/Rakefile'
-    - '**/config.ru'
   Exclude:
     - 'db/**/*'
     - 'config/**/*'
     - 'script/**/*'
     - 'vendor/**/*'
     - 'node_modules/**/*'
-    - !ruby/regexp /old_and_unused\.rb$/
     # The parser gem fails to parse this file with out current Ruby version.
     - 'spec/factories.rb'
 
@@ -174,28 +170,28 @@ Lint/AssignmentInCondition:
   StyleGuide: http://relaxed.ruby.style/#lintassignmentincondition
 
 Metrics/AbcSize:
-  Enabled: false
+  Max: 15
 
 Metrics/BlockNesting:
-  Enabled: false
+  Max: 3
 
 Metrics/ClassLength:
-  Enabled: false
+  Max: 100
 
 Metrics/ModuleLength:
-  Enabled: false
+  Max: 100
 
 Metrics/CyclomaticComplexity:
-  Enabled: false
+  Max: 6
 
 Metrics/LineLength:
-  Enabled: false
+  Max: 80
 
 Metrics/MethodLength:
-  Enabled: false
+  Max: 10
 
 Metrics/ParameterLists:
-  Enabled: false
+  Max: 5
 
 Metrics/PerceivedComplexity:
-  Enabled: false
+  Max: 7