Updated badge. [ci skip]

Author: dblock

README.md

@@ -1,7 +1,7 @@
 Slack Ruby Bot Server
 =====================
 
-[![Build Status](https://travis-ci.org/dblock/slack-ruby-bot-server-sample.svg?branch=master)](https://travis-ci.org/dblock/slack-ruby-bot-server-sample)
+[![Build Status](https://travis-ci.org/slack-ruby/slack-ruby-bot-server-sample.svg?branch=master)](https://travis-ci.org/slack-ruby/slack-ruby-bot-server-sample)
 
 ### What is this?