added coveralls icon to readme

Author: tzikis

README.md

@@ -1,4 +1,6 @@
-This repository is part of the [codebender.cc](http://www.codebender.cc) maker and artist web platform.  [![Build Status](https://travis-ci.org/codebendercc/compiler.svg?branch=master)](https://travis-ci.org/codebendercc/compiler)
+This repository is part of the [codebender.cc](http://www.codebender.cc) maker and artist web platform. 
+
+[![Build Status](https://travis-ci.org/codebendercc/compiler.svg?branch=master)](https://travis-ci.org/codebendercc/compiler) [![Coverage Status](https://img.shields.io/coveralls/codebendercc/compiler.svg)](https://coveralls.io/r/codebendercc/compiler?branch=master)
 
 ## And what's that?