"Unable to verify the Docker daemon is listening" at server provisioning

Hi!

Thank you for this amazing container. We're testing it at git.coopdevs.org and we had experimented this issue at new machine creation:

Error creating machine: Error running provisioning: Unable to verify the Docker daemon is listening: Maximum number of retries (10) exceeded

I was able to solve with the workaround provided in an issue on docker-machine-driver-hetzner repository

[[runners]]
  [runners.machine]
    MachineOptions = [
      """hetzner-user-data=
        #cloud-config
        runcmd:
          - |
            while sleep 1; do
              if [ -e /etc/systemd/system/docker.service.d/10-machine.conf ]; then
                sleep 15
                systemctl restart docker
                break
              fi
            done &
      """
    ]

I am working on a merge request to add this to README.

Best,

Lai