Add travis notification to slack room

Send build status to slack. RoomID is stored in travis as an environment variable

Author: loafyloaf

.travis.yml

@@ -6,6 +6,13 @@ sudo: required
 
 dist: trusty
 
+notifications:
+ slack:
+ rooms:
+ - "$SLACK_ROOM"
+ on_pull_requests: false
+ on_success: change
+
 services:
  - docker