Adding Code Climate badge to readme

Author: e3betht

README.md

@@ -1,6 +1,6 @@
 # SocketClient Component
 
-[![Build Status](https://secure.travis-ci.org/reactphp/socket-client.png?branch=master)](http://travis-ci.org/reactphp/socket-client)
+[![Build Status](https://secure.travis-ci.org/reactphp/socket-client.png?branch=master)](http://travis-ci.org/reactphp/socket-client) [![Code Climate](https://codeclimate.com/github/reactphp/socket-client/badges/gpa.svg)](https://codeclimate.com/github/reactphp/socket-client)
 
 Async Connector to open TCP/IP and SSL/TLS based connections.