Update .gitlab-ci.yml file

.gitlab-ci.yml

-image: docker:stable
+image: python:3
+
+stages:
+  - test
+  - build
+  - deploy
+
+test:
+  stage: test
+  script:
+    - cd backend/secfit
+    - apt-get update -qy
+    - pip install -r requirements.txt
+    - python manage.py test
 
 build:
+  image: docker:19.03.12
   stage: build
+  variables:
+    DOCKER_HOST: tcp://docker:2375
+    DOCKER_TLS_CERTDIR: ""
+  services:
+    - docker:19.03.12-dind
+  script:
+    - docker build --pull -t https://gitlab.stud.idi.ntnu.no/vegarms/tdt4242-base
+    - docker run https://gitlab.stud.idi.ntnu.no/vegarms/tdt4242-base
+
+deploy:
+  stage: deploy
   script:
-    - docker-compose build
\ No newline at end of file
+    - apt-get update -yq
+    - apt-get install -y ruby-dev
+    - gem install dpl
+    - dpl --provider=heroku --app=secfit-group15 --api_key=$HEROKU_API_KEY
+  only:
+    - master