Add coverity scan build status image to Readme

README.md

@@ -3,6 +3,8 @@ OpenMW: A reimplementation of The Elder Scrolls III: Morrowind
 
 [![Build Status](https://travis-ci.org/OpenMW/openmw.svg?branch=coverity_scan)](https://travis-ci.org/OpenMW/openmw)
 
+[![Coverity Scan Build Status](https://scan.coverity.com/projects/3740/badge.svg)](https://scan.coverity.com/projects/3740)
+
 OpenMW is an attempt at recreating the engine for the popular role-playing game
 Morrowind by Bethesda Softworks. You need to own and install the original game for OpenMW to work.