Added docker building to travis. This is just a

Thomas Miller · Thomas Miller · commit d8bbd19de59f · 2017-05-09T11:58:19.000+10:00
test to check configuration at the moment.
diff --git a/.travis.yml b/.travis.yml
@@ -1,5 +1,13 @@
 language: java
-dist: trusty
 jdk:
     - oraclejdk8
     - openjdk8
+
+dist: trusty
+sudo: required
+
+services:
+    - docker
+
+after_success:
+    - docker build .
