Add travis build status indicator for master

Author: nlitwin

README.md

@@ -1,5 +1,5 @@
 Dev: [![Build Status](https://travis-ci.org/appirio-tech/topcoder-app.svg?branch=dev)](https://travis-ci.org/appirio-tech/topcoder-app)
-
+Master: [![Build Status](https://travis-ci.org/appirio-tech/topcoder-app.svg?branch=master)](https://travis-ci.org/appirio-tech/topcoder-app)
 # Topcoder-App
 
 This repository houses any new topcoder pages or refactored Angular apps/pages from the tc-site repository.