Build image in tests

Build again in test step, hopefully it will using cached layers of docker engine.

.gitlab-ci.yml

 image: python:3.6
 
 before_script:
-  - docker info
   - git submodule sync --recursive
   - git submodule update --init --recursive
 
@@ -17,4 +16,5 @@ build-local:
 
 test:
   script:
+    - docker build --tag recircle-backend:1.0 .
     - docker run recircle-backend pipenv run python manage.py test