add a Rakefile and gems for testing

Rakefile

@@ -0,0 +1,12 @@
+require 'bundler/gem_tasks'
+require 'rubocop/rake_task'
+require 'rspec/core/rake_task'
+
+desc 'Run Rubocop'
+RuboCop::RakeTask.new(:rubocop) do |task|
+  task.patterns = ['bin/*.rb', 'lib/**/*.rb']
+end
+
+RSpec::Core::RakeTask.new(:spec)
+
+task default: [:rubocop, :spec]

aws-cleaner.gemspec

@@ -10,12 +10,15 @@ Gem::Specification.new do |s|
   s.homepage    = 'https://github.com/eheydrick/aws-cleaner'
   s.license     = 'MIT'
 
-  s.add_development_dependency 'rubocop', '~> 0.43.0'
+  s.add_development_dependency 'bundler', '~> 1.12'
+  s.add_development_dependency 'rake', '~> 12.0'
+  s.add_development_dependency 'rspec', '~> 3.5'
+  s.add_development_dependency 'rubocop', '~> 0.46.0'
 
   s.add_runtime_dependency 'aws-sdk-core', '~> 2.0'
   s.add_runtime_dependency 'chef-api', '~> 0.5'
   s.add_runtime_dependency 'hipchat', '~> 1.5'
-  s.add_runtime_dependency 'rest-client', '~> 2 '
+  s.add_runtime_dependency 'rest-client', '~> 2'
   s.add_runtime_dependency 'slack-poster', '~> 2.2'
   s.add_runtime_dependency 'trollop', '~> 2.1'
 end