trying to fix docker

.gitlab-ci.yml

@@ -16,7 +16,7 @@ build:
     - echo $DOCKERHUBUSER
     - echo $DOCKERHUBPASSWORD
     - docker login -u $DOCKERHUBUSER -p $DOCKERHUBPASSWORD docker.io
-    - docker build --tag=l1ll1/strudel2_backend .
+    - docker build --tag=l1ll1/strudel2_backend:$CI_COMMIT_BRANCH .
     - docker push l1ll1/strudel2_backend:$CI_COMMIT_BRANCH
   tags:
     - build_strudel2_backend