Lets try to automate this build a bit

This doesn't rebuild on subproject changes... this is something that
will need fixed.

.gitlab-ci.yml

@@ -0,0 +1,10 @@
+build_image:
+  image: docker:git
+  services:
+  - docker:dind
+  script:
+    - docker build -f docker/Dockerfile -t asia.gcr.io/linuxconfsydney/symposion_app .
+    - docker login -u _json_key -p "$GOOGLE_KEY" https://asia.gcr.io
+    - docker push asia.gcr.io/linuxconfsydney/symposion_app:latest
+  only:
+    - master