fixing docker tags

.gitlab-ci.yml

@@ -34,7 +34,7 @@ build:image:
   tags:
       - privileged
   script:
-      - docker build -t $DOCKER_IMAGE_TAG -f docker/Dockerfile --build-arg SDIST=dist/$SDIST .
+      - docker build -t $DOCKER_USER/$DOCKER_IMAGE_TAG -f docker/Dockerfile --build-arg SDIST=dist/$SDIST .
       - docker save $DOCKER_IMAGE_TAG -o image.tar
   dependencies:
       - build:sdist
@@ -59,7 +59,7 @@ test:
           -e REDIS_HOST=$REDIS_PORT_6379_TCP_ADDR
           -e RABBITMQ_HOST=$RABBITMQ_PORT_5672_TCP_ADDR
           $DOCKER_IMAGE_TAG
-          sh -c "celery worker -D -A fractalis:celery -l debug
+          sh -c "celery worker -D -A fractalis:celery -l debug --concurrency=1
           && pip3 install -r requirements.txt
           && flake8
           && pytest tests"