Adds codecov badge.

Boris Malensek · Boris Malensek · commit c2fc912a8a90 · 2016-03-17T11:24:38.000+01:00
diff --git a/README.md b/README.md
@@ -2,6 +2,7 @@
 
 [![Build Status](https://travis-ci.org/zalando/scala-jsonapi.svg)](https://travis-ci.org/zalando/scala-jsonapi)
 [![Coverage Status](https://coveralls.io/repos/zalando/scala-jsonapi/badge.svg?branch=master&service=github)](https://coveralls.io/github/zalando/scala-jsonapi?branch=master)
+[![codecov.io](https://codecov.io/github/zalando/scala-jsonapi/coverage.svg?branch=master)](https://codecov.io/github/zalando/scala-jsonapi?branch=master)
 [![Join the chat at https://gitter.im/zalando/scala-jsonapi](https://badges.gitter.im/zalando/scala-jsonapi.svg)](https://gitter.im/zalando/scala-jsonapi?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 
 A Scala library for producing JSON output based on [JSON API specification](http://jsonapi.org/). 
