Merge pull request #298 from bugsnag/code-cov-badge

Add code coverage badge

README.md

@@ -1,6 +1,7 @@
 # Bugsnag exception reporter for Android
 [![Documentation](https://img.shields.io/badge/documentation-latest-blue.svg)](https://docs.bugsnag.com/platforms/android/)
 [![Build status](https://travis-ci.org/bugsnag/bugsnag-android.svg?branch=master)](https://travis-ci.org/bugsnag/bugsnag-android)
+[![Coverage Status](https://coveralls.io/repos/github/bugsnag/bugsnag-android/badge.svg?branch=master)](https://coveralls.io/github/bugsnag/bugsnag-android?branch=master)
 [![Method count and size](https://img.shields.io/badge/Methods%20and%20size-core:%20742%20|%20deps:%2032%20|%2090%20KB-e91e63.svg)](http://www.methodscount.com/?lib=com.bugsnag%3Abugsnag-android%3A4.0.0)
 
 Get comprehensive [Android crash reports](https://www.bugsnag.com/platforms/android/) to quickly debug errors.