@docker-training,
Absolutely! I don't see any problem doing this (it comes from the ["PostgreSQL" example](http://docs.docker.io/examples/postgresql_service/)).

However, I think we should inform the reader somehow about the output of this command. It can look scary at first. What do you think of putting a reminder about that?

BTW - Using `DEBIAN_FRONTEND` is mentioned as a comment on this article: http://docs.docker.io/examples/postgresql_service/