Add test badge

Author: luin

README.md

@@ -1,6 +1,6 @@
 # Redis Commands
 
-Redis commands.
+[![Build Status](https://travis-ci.org/luin/redis-commands.png?branch=master)](https://travis-ci.org/luin/redis-commands)
 
 This module exports all the commands that Redis supports, using the API of http://redis.io/commands.json. The version of this module should equal to the Redis version of the commands.