build:
   image: docker:latest
   services:
   - docker:dind
   stage: build
   script:
     - docker login -u gitlab-ci-token -p $CI_JOB_TOKEN $CI_REGISTRY
     - docker build --pull --tag $CI_REGISTRY_IMAGE:latest --tag $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA .
     - docker push $CI_REGISTRY_IMAGE:master
     - docker push $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA