Add coverage status

[ci skip]

Author: aptx4869

README.md

@@ -5,6 +5,9 @@
 [![License](http://img.shields.io/badge/license-MIT-brightgreen.svg)](http://opensource.org/licenses/MIT)
 [![Build Status: Linux](https://travis-ci.org/aptx4869/CommentCoreLibrary.svg?branch=auto-test)](https://travis-ci.org/aptx4869/CommentCoreLibrary)
 <!--[![Build Status: Linux](https://travis-ci.org/jabbany/CommentCoreLibrary.svg?branch=master)](https://travis-ci.org/jabbany/CommentCoreLibrary)-->
+[![Coverage Status](https://coveralls.io/repos/aptx4869/CommentCoreLibrary/badge.png?branch=auto-test)](https://coveralls.io/r/aptx4869/CommentCoreLibrary?branch=auto-test)
+<!--[![Coverage Status](https://img.shields.io/coveralls/jabbany/CommentCoreLibrary.svg)](https://coveralls.io/r/jabbany/CommentCoreLibrary?branch=master)-->
+
 The CommentCoreLibrary is a set of Javascript modules that make up the
 core controller for comments streaming on top of timed media (video or audio).
 It is intended as a catalyst for the development of timed "danmaku" comments