add coverage widget

README.rst

@@ -1,7 +1,7 @@
 `Verktyg <verktyg_>`_
 =====================
 
-|build-status|
+|build-status| |coverage|
 
 Verktyg is a web framework built on `werkzeug`_.
 
@@ -113,6 +113,9 @@ Please post any problems or feature requests using the `issue tracker <issues_>`
 .. |build-status| image:: https://travis-ci.org/bwhmather/verktyg.png?branch=master
     :target: http://travis-ci.org/bwhmather/verktyg
     :alt: Build Status
+.. |coverage| image:: https://coveralls.io/repos/bwhmather/verktyg/badge.png?branch=develop
+    :target: https://coveralls.io/r/bwhmather/verktyg?branch=develop
+    :alt: Coverage
 .. _verktyg: https://github.com/bwhmather/verktyg
 .. _werkzeug: https://github.com/mitsuhiko/werkzeug
 .. _issues: https://github.com/bwhmather/verktyg/issues