add appveyor badge

README.md

@@ -5,8 +5,11 @@ mozregression is an interactive regression range finder for Mozilla nightly and
 [![Python versions](https://pypip.in/py_versions/mozregression/badge.svg)](https://pypi.python.org/pypi/mozregression/)
 [![License](https://pypip.in/license/mozregression/badge.svg)](https://pypi.python.org/pypi/mozregression/)
 
-[![Build Status](https://travis-ci.org/mozilla/mozregression.svg?branch=master)](https://travis-ci.org/mozilla/mozregression)
-[![Coverage Status](https://img.shields.io/coveralls/mozilla/mozregression.svg)](https://coveralls.io/r/mozilla/mozregression)
+Build status:
+ - Linux:
+   [![Linux Build Status](https://travis-ci.org/mozilla/mozregression.svg?branch=master)](https://travis-ci.org/mozilla/mozregression)
+   [![Coverage Status](https://img.shields.io/coveralls/mozilla/mozregression.svg)](https://coveralls.io/r/mozilla/mozregression)
+ - Windows: [![Windows Build status](https://ci.appveyor.com/api/projects/status/ukv1ariar1jboxar/branch/master?svg=true)](https://ci.appveyor.com/project/parkouss/mozregression/branch/master)
 
 For more information see: