Update .travis.yml

Author: almerico

.travis.yml

@@ -3,3 +3,9 @@ sudo: required
 
 services:
   - docker
+  
+after_success:
+  - if [ "$TRAVIS_BRANCH" == "master" ]; then
+    docker login -u="$DOCKER_USERNAME" -p="$DOCKER_PASSWORD";
+    docker push introproventures/graphql-jpa-query-example:latest;
+    fi