Update `docker-cloud.yml`.
Update `docker-cloud.yml`.

* Reflect the style output by Docker Cloud.

* Add `autoredeploy: true` (commented out).

* Enable `postgres` service by default. Don't assume people want to
  deploy to an external persistent database (like Amazon RDS). If they
  are deploying the ICEkit image standalone, it's probably a demo.

* Always restart services.

* Add an `icekit` deployment tag. We don't want to accidentally deploy
  services all over someone's Docker Cloud infrastructure. They should
  be able to easily add this tag to the node cluster(s) they want to
  use, or remove the deployment tag from the stack file.

* Add a volume for the project template `var` directory.

* Use `example.com` as the default domain, instead of `*`.

* Add `letsencrypt` service, which is expected to handle port all HTTP
  traffic, respond to ACMI challenges and redirect to HTTPS.

* Add missing links to `celerybeat` and `celeryflower` services.

* Use IC version of `dockercloud-haproxy` service.

* Add `X-Forwarded-Proto` header.

ic-labs/django-icekit,ic-labs/django-icekit,ic-labs/django-icekit,ic-labs/django-icekit