gitlab: renamed script parameter start -> app:start
gitlab: add db operation commands the app:db: prefix
gitlab: add help command the app: prefix
gitlab: align help text
Merge branch 'feature/cli-reborn'
gitlab: added the capability to run any installed *nix command

eg.
docker run -i -t sameersbn/gitlab top -d1
docker run -i -t sameersbn/gitlab /bin/bash -i
...and so on.
gitlab: exposed GITLAB_SIGNUP parameter to enable/disable user signup.
README: document GITLAB_SIGNUP setting
Merge branch 'feature/signups'