Docker composer for CoreOS Cloud config

coreos.yml

files:
    - path: /opt/bin/docker-compose
      filesystem: root
      mode: 0744
      contents:
        remote:
          url: https://github.com/docker/compose/releases/download/1.21.2/docker-compose-Linux-x86_64
          verification:
            hash:
              function: sha512
              sum: 5A9CCBE01CBF585732907F38FBACC21AECD2EDC9351BD1EE91DF750740A7FFF9D73BD489D708087D9D8892AD8F448A78A8EE401D240A51D0202ED0C08E30BF88