add coverage to README

README.md

@@ -3,7 +3,7 @@
 [![GoDoc](https://godoc.org/github.com/carlostrub/sisyphus?status.svg)](https://godoc.org/github.com/carlostrub/sisyphus)
 [![Documentation](https://readthedocs.org/projects/sisyphus/badge/?version=latest)](http://sisyphus.readthedocs.org/en/latest/?badge=latest)
 [![Codebeat](https://codebeat.co/badges/64615809-e3c4-4267-a049-eaec20ad63b5)](https://codebeat.co/projects/github-com-carlostrub-sisyphus-master)
-[![Coverage](https://coveralls.io/repos/github/carlostrub/sisyphus/badge.svg?branch=master)](https://coveralls.io/github/carlostrub/sisyphus?branch=master)
+[![Coverage](https://gocover.io/_badge/github.com/carlostrub/sisyphus?0 "Coverage")](http://gocover.io/github.com/carlostrub/sisyphus)
 
 # sisyphus
 Intelligent, easy to configure Spam cleaner