Add coverage to readme
diff --git a/README.rst b/README.rst
index 1cb9203..e7c116c 100644
--- a/README.rst
+++ b/README.rst
@@ -7,6 +7,7 @@
 
 .. image:: https://badge.fury.io/py/gstack.png
 .. image:: https://api.travis-ci.org/NOPping/gstack.png
+.. image:: https://coveralls.io/repos/NOPping/gstack/badge.png