Add coverity scan badge to readme
diff --git a/README.md b/README.md
index 434cc19..debf16e 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,7 @@ libgit2 - the Git linkable library
==================================
[![Build Status](https://secure.travis-ci.org/libgit2/libgit2.png?branch=development)](http://travis-ci.org/libgit2/libgit2)
+[![Coverity Scan Build Status](https://scan.coverity.com/projects/639/badge.svg)](https://scan.coverity.com/projects/639)
`libgit2` is a portable, pure C implementation of the Git core methods provided as a
re-entrant linkable library with a solid API, allowing you to write native