Include coveralls for ruby 2.2

Author: oreoshake

Gemfile

@@ -10,6 +10,6 @@ group :test do
   gem 'rspec', '>= 3.1'
   gem 'growl'
   gem 'rb-fsevent'
-  gem 'coveralls', :platforms => [:ruby_19, :ruby_20, :ruby_21, :ruby_21]
+  gem 'coveralls', :platforms => [:ruby_19, :ruby_20, :ruby_21, :ruby_21, :ruby_22]
   gem 'i18n', '< 0.7.0', :platforms => [:ruby_18]
 end