Update Readme.md

Author: Kenneth Reitz

Readme.md

@@ -4,6 +4,8 @@ Heroku buildpack: Python
 This is a [Heroku buildpack](http://devcenter.heroku.com/articles/buildpacks) for Python apps.
 It uses [virtualenv](http://www.virtualenv.org/) and [pip](http://www.pip-installer.org/).
 
+[![Build Status](https://secure.travis-ci.org/heroku/heroku-buildpack-python.png?branch=master)](http://travis-ci.org/heroku/heroku-buildpack-python)
+
 Usage
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