Buildkite Crystal pipeline

pipeline.yml

steps:
  - command: 
    - "shards install"
    - "tar pczf lib.tar.gz lib/"
    label: "Install shards"
    artifact_paths: "lib.tar.gz"
    plugins:
      - docker#v2.1.0:
          image: "crystallang/crystal:latest"
          always-pull: true

  - wait

  - command: 
    - "buildkite-agent artifact download lib.tar.gz ./"
    - "tar xzvf lib.tar.gz"
    - "crystal spec"
    label: "Run specs"
    plugins:
      - docker#v2.1.0:
          image: "crystallang/crystal:latest"
          always-pull: true

  - command: 
    - "buildkite-agent artifact download lib.tar.gz ./"
    - "tar xzvf lib.tar.gz"
    - "crystal docs"
    - "tar pczf docs.tar.gz docs/"
    label: "Generate API docs"
    artifact_paths: "docs.tar.gz"
    plugins:
      - docker#v2.1.0:
          image: "crystallang/crystal:latest"
          always-pull: true

  - wait

  - command: 
    - "git checkout -B gh-pages"
    - "buildkite-agent artifact download docs.tar.gz ./"
    - "tar xzvf docs.tar.gz"
    - "cd docs && git add ."
    - "git commit -m 'Deploy from the Buildkite pipeline' && git push origin api-docs || echo 'Skipping the deploy'"
    label: "Deploy API docs"
    branches: "master"