add travis build badge

Author: niccokunzmann

README.md

@@ -1,5 +1,6 @@
 # intro
 
+[![Build Status](https://travis-ci.org/CoderDojoPotsdam/intro.svg?branch=master)](https://travis-ci.org/CoderDojoPotsdam/intro)
 [![Join the chat at https://gitter.im/CoderDojoPotsdam/intro](https://badges.gitter.im/CoderDojoPotsdam/intro.svg)](https://gitter.im/CoderDojoPotsdam/intro?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 Das ist die neue Introseite der CoderDojo Materialien