[travis] white list redis (#650)

.travis.yml

 before_script:
   - gem install awesome_bot
 script:
-  - awesome_bot README.md --white-list amazon.com,igor.io,hoa-project.net
+  - awesome_bot README.md --white-list amazon.com,igor.io,hoa-project.net,redis.io
 notifications:
   email: false