Add gitter hooks to travis

Author: R. Tyler Croy

.travis.yml

@@ -1,3 +1,10 @@
 language: java
 jdk:
 - oraclejdk8
+notifications:
+  webhooks:
+    urls:
+      - https://webhooks.gitter.im/e/ad76bd3a7bd257f0159c
+    on_success: change  # options: [always|never|change] default: always
+    on_failure: always  # options: [always|never|change] default: always
+    on_start: false     # default: false