Merge pull request #2121 from mboersma/build-status-badge

docs(README): add build status badge for CI test-master job

Author: mboersma

README.md

@@ -2,6 +2,7 @@
 
 Deis (pronounced DAY-iss) is an open source PaaS that makes it easy to deploy and manage applications on your own servers. Deis builds upon [Docker](http://docker.io/) and [CoreOS](http://coreos.com) to provide a lightweight PaaS with a [Heroku-inspired](http://heroku.com) workflow.
 
+[![Build Status](http://ci.deis.io/buildStatus/icon?job=test-master)](http://ci.deis.io/job/test-master/)
 [![Current Release](http://img.shields.io/badge/release-v0.13.0-blue.svg)](https://github.com/deis/deis/releases/tag/v0.13.0)
 
 ![Deis Graphic](https://s3-us-west-2.amazonaws.com/deis-images/deis-graphic.png)