Add Rubocop

* Add rubocop as test/dev dependency
* Add rubocop rake task
* Add current Fastly rubocop style configuration

.rubocop.yml

@@ -0,0 +1,35 @@
+# inherit_from:
+  # - rubocop-todo.yml
+
+LineLength:
+  Enabled: false
+
+HashSyntax:
+  Enabled: false
+
+BracesAroundHashParameters:
+  Enabled: false
+
+BlockNesting:
+  Enabled: false
+
+AssignmentInCondition:
+  Enabled: false
+
+CollectionMethods:
+  Enabled: false
+
+CyclomaticComplexity:
+  Enabled: false
+
+MethodLength:
+  Enabled: false
+
+PerlBackrefs:
+  Enabled: false
+
+RescueModifier:
+  Enabled: false
+
+HandleExceptions:
+  Enabled: false

Gemfile

@@ -7,4 +7,5 @@ group :development, :test do
   gem 'rdoc', '~> 4.1.1'
   gem 'minitest', '~> 5.3.4'
   gem 'pry'
+  gem 'rubocop'
 end

Rakefile

@@ -1,6 +1,4 @@
 require 'bundler/gem_tasks'
-require 'rake/testtask'
-require 'rdoc/task'
 
 desc 'Run library from within a Pry console'
 task :console do
@@ -17,6 +15,17 @@ namespace :clean do
   end
 end
 
+require 'rubocop/rake_task'
+
+desc 'Run rubocop'
+RuboCop::RakeTask.new(:rubocop) do |task|
+  task.patterns = ['lib/**/*.rb', 'test/**/*.rb']
+  task.formatters = ['fuubar']
+  task.fail_on_error = true
+end
+
+require 'rdoc/task'
+
 RDoc::Task.new do |rdoc|
   rdoc.rdoc_dir = 'doc'
   rdoc.main = 'README.md'
@@ -30,6 +39,8 @@ namespace :test do
   end
 end
 
+require 'rake/testtask'
+
 Rake::TestTask.new do |t|
   t.libs << 'test'
   t.test_files = FileList['test/*test.rb']