use codebeat for gpa rating

Author: tiagoschenkel

README.md

@@ -3,7 +3,7 @@ SignalsJS
 
 [![Gitter chat](https://badges.gitter.im/RobotlegsJS/RobotlegsJS.svg)](https://gitter.im/RobotlegsJS/RobotlegsJS)
 [![Build Status](https://travis-ci.org/RobotlegsJS/SignalsJS.svg?branch=master)](https://travis-ci.org/RobotlegsJS/SignalsJS)
-[![Code Climate](https://codeclimate.com/github/RobotlegsJS/SignalsJS/badges/gpa.svg)](https://codeclimate.com/github/RobotlegsJS/SignalsJS)
+[![codebeat badge](https://codebeat.co/badges/88ef8956-4c0f-4a25-b35d-7fab824234e3)](https://codebeat.co/projects/github-com-robotlegsjs-signalsjs-master)
 [![Test Coverage](https://codeclimate.com/github/RobotlegsJS/SignalsJS/badges/coverage.svg)](https://codeclimate.com/github/RobotlegsJS/SignalsJS/coverage)
 [![npm version](https://badge.fury.io/js/%40robotlegsjs%2Fsignals.svg)](https://badge.fury.io/js/%40robotlegsjs%2Fsignals)
 [![Greenkeeper badge](https://badges.greenkeeper.io/RobotlegsJS/SignalsJS.svg)](https://greenkeeper.io/)