title: .gitlab-ci.yml error: "apk: command not found"
body: <p>I have the following <strong><em>.gitlab-ci.yml</em></strong> file:</p>
  
  <pre><code>image: docker
  
  services:
    - docker:dind
  
  stages:
    - test
    - build
    - deploy
  
  test:
    stage: test
    before_script:
      - apk add --update -y python-pip
      - pip install docker-compose
    script:
      - echo "Testing the app"
      - docker-compose run app sh -c "python manage.py test &amp;&amp; flake8"
  
  build:
    stage: build
    only:
      - develop
      - production
      - feature/deploy-debug-gitlab
    before_script:
      - apk add --update -y python-pip
      - pip install docker-compose
    script:
      - echo "Building the app"
      - docker-compose build
  
  deploy:
    stage: deploy
    only:
      - master
      - develop
      - feature/deploy
      - feature/deploy-debug-gitlab
    before_script:
      - apk add --update -y python-pip
      - pip install docker-compose
    script:
      - echo "Deploying the app"
      - docker-compose up -d
    environment: production
    when: manual
  
  </code></pre>
  
  <p>When the Gitlab runner executes it, I get the following error:</p>
  
  <pre><code>$ apk add --update -y python-pip
  bash: line 82: apk: command not found
  ERROR: Job failed: exit status 1
  </code></pre>
  
  <p>How am I supposed to install apk? Or what image other than <code>docker</code> should I be using to run this <code>gitlab-ci.yml</code> file?</p>