Update .travis.yml

Add gitter

Author: jadonk

.travis.yml

@@ -7,3 +7,12 @@ after_script:
 notifications:
   irc:
     - "chat.freenode.net#beagle-bonescript"
+notifications:
+  webhooks:
+    urls:
+      - https://webhooks.gitter.im/e/800e4efb92aa7f8eda15
+    on_success: change  # options: [always|never|change] default: always
+    on_failure: always  # options: [always|never|change] default: always
+    on_start: false     # default: false
+
+