diff --git a/.gitignore b/.gitignore
index 9e626c9..7776649 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,3 +9,4 @@ spec/dummy/tmp/
 spec/dummy/.sass-cache
 Gemfile.lock
 gemfiles/*.lock
+coverage/
diff --git a/README.md b/README.md
index 128e310..ff96cdb 100644
--- a/README.md
+++ b/README.md
@@ -2,5 +2,6 @@
 
 [![Build Status](https://secure.travis-ci.org/hyoshida/poteti.png)](http://travis-ci.org/hyoshida/poteti)
 [![Code Climate](https://codeclimate.com/github/hyoshida/poteti.png)](https://codeclimate.com/github/hyoshida/poteti)
+[![Coverage Status](https://coveralls.io/repos/hyoshida/poteti/badge.png)](https://coveralls.io/r/hyoshida/poteti)
 
 This project rocks and uses MIT-LICENSE.
diff --git a/poteti.gemspec b/poteti.gemspec
index eca4cca..96a6ded 100644
--- a/poteti.gemspec
+++ b/poteti.gemspec
@@ -25,4 +25,5 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'rubocop'
   s.add_development_dependency 'rspec-rails'
   s.add_development_dependency 'factory_girl_rails'
+  s.add_development_dependency 'coveralls'
 end
diff --git a/spec/rails_helper.rb b/spec/rails_helper.rb
index ef0a90a..0906cb3 100644
--- a/spec/rails_helper.rb
+++ b/spec/rails_helper.rb
@@ -1,5 +1,9 @@
 # This file is copied to spec/ when you run 'rails generate rspec:install'
 ENV['RAILS_ENV'] ||= 'test'
+
+require 'coveralls'
+Coveralls.wear!('rails')
+
 require 'spec_helper'
 require File.expand_path('../dummy/config/environment', __FILE__)
 require 'rspec/rails'