Added a badge to the README showing coverage
diff --git a/README.rst b/README.rst
index 0a57707..4379bb5 100644
--- a/README.rst
+++ b/README.rst
@@ -4,6 +4,9 @@
.. image:: https://travis-ci.org/alex/cryptography.png?branch=master
:target: https://travis-ci.org/alex/cryptography
+.. image:: https://coveralls.io/repos/alex/cryptography/badge.png?branch=master
+ :target: https://coveralls.io/r/alex/cryptography?branch=master
+
``cryptography`` is a package designed to expose cryptographic primitives and
recipes to Python developers.