Only push latest docker tag on release

.gitlab-ci.yml

@@ -87,7 +87,6 @@ build docker image:
     - docker-compose build --build-arg install_dev_requirements=0 --build-arg source_commit=$(git rev-parse HEAD) web
     - docker-compose run --rm web test
     - docker tag $DOCKER_LATEST $DOCKER_TAG
-    - docker push $DOCKER_LATEST
     - docker push $DOCKER_TAG
   variables:
     DOCKER_LATEST: registry.hub.docker.com/thalia/concrexit:latest
@@ -109,10 +108,13 @@ tag docker image:
   script:
     - docker pull $DOCKER_TAG
     - docker tag $DOCKER_TAG $DOCKER_TAG_PRODUCTION
+    - docker tag $DOCKER_TAG $DOCKER_LATEST
     - docker push $DOCKER_TAG_PRODUCTION
+    - docker push $DOCKER_LATEST
   variables:
     DOCKER_TAG: registry.hub.docker.com/thalia/concrexit:$CI_COMMIT_SHA
     DOCKER_TAG_PRODUCTION: registry.hub.docker.com/thalia/concrexit:$CI_COMMIT_TAG
+    DOCKER_LATEST: registry.hub.docker.com/thalia/concrexit:latest
 
 
 cache: