use cookstyle for linting

Signed-off-by: Martin Schurz <Martin.Schurz@t-systems.com>

.rubocop.yml

@@ -2,31 +2,3 @@
 AllCops:
   Exclude:
   - vendor/**/*
-Documentation:
-  Enabled: false
-ParameterAlignment:
-  Enabled: true
-HashSyntax:
-  Enabled: true
-LineLength:
-  Enabled: false
-EmptyLinesAroundBlockBody:
-  Enabled: false
-Style/IfUnlessModifier:
-  Enabled: false
-MethodLength:
-  Max: 40
-NumericLiterals:
-  MinDigits: 10
-Metrics/BlockLength:
-  Max: 35
-Metrics/CyclomaticComplexity:
-  Max: 10
-Metrics/PerceivedComplexity:
-  Max: 10
-Metrics/AbcSize:
-  Max: 30
-# Lint/AmbiguousBlockAssociation is incompatible with RSpec
-# https://github.com/rubocop-hq/rubocop/issues/4222
-Lint/AmbiguousBlockAssociation:
-  Enabled: false

Gemfile

@@ -2,6 +2,7 @@
 
 source 'https://rubygems.org'
 
+gem 'cookstyle'
 gem 'highline'
 gem 'rack'
 gem 'rake'

Rakefile

@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+require 'cookstyle'
 require 'rake/testtask'
 require 'rubocop/rake_task'
 
@@ -9,6 +10,10 @@ task :rubocop do
   RuboCop::RakeTask.new
 end
 
+RuboCop::RakeTask.new(:cookstyle) do |task|
+  task.options << '--display-cop-names'
+end
+
 # lint the project
 desc 'Run robocop linter'
 task lint: [:rubocop]