Add coveralls

Author: tmcw

README.md

@@ -1,4 +1,7 @@
 # documentation-theme-utils
 
+[![Circle CI](https://circleci.com/gh/documentationjs/documentation-theme-utils/tree/master.svg?style=svg)](https://circleci.com/gh/documentationjs/documentation-theme-utils/tree/master)
+[![Coverage Status](https://coveralls.io/repos/documentationjs/documentation-theme-utils/badge.svg?branch=master&service=github)](https://coveralls.io/github/documentationjs/documentation-theme-utils?branch=master)
+
 Utilities that help in the process of building theme modules
 for documentation.js.