message: migrate to ubuntu 18 for new droplets
diff: @@ -387,7 +387,7 @@ export class DigitaloceanServerRepository implements server.ManagedServerReposit
  const dropletSpec = {
  installCommand,
  size: MACHINE_SIZE,
  - image: 'docker',
  + image: 'docker-18-04',
  tags: [SHADOWBOX_TAG],
  };
  return onceKeyPair
  