Add Coverity badge

diff --git a/README b/README
index aa05516..6e21322 100644
--- a/README
+++ b/README

@@ -1,6 +1,7 @@
 [![Build Status](https://travis-ci.org/harfbuzz/harfbuzz.svg)](https://travis-ci.org/harfbuzz/harfbuzz)
 [![Build status](https://ci.appveyor.com/api/projects/status/0t0flrxpstj9lb9w?svg=true)](https://ci.appveyor.com/project/harfbuzz/harfbuzz)
 [![CircleCI](https://circleci.com/gh/harfbuzz/harfbuzz.svg?style=svg)](https://circleci.com/gh/harfbuzz/harfbuzz)
+[![Coverity](https://img.shields.io/coverity/scan/5450.svg)](https://scan.coverity.com/projects/behdad-harfbuzz)
 [![Coverage Status](https://img.shields.io/coveralls/harfbuzz/harfbuzz.svg)](https://coveralls.io/r/harfbuzz/harfbuzz)
 [ABI Tracker](http://abi-laboratory.pro/tracker/timeline/harfbuzz/)