Docker Support

https://github.com/pulp/crane/blob/master/docs/index.rst

Current docs explain what Crane is and what the configuration values should be, but does not cover step-by-step installation or example usage.

Docs should cover

• Where to configure apache to "Ensure that Apache is listening on the specified port."
• SELinux. There is no policy, so quickstart should recommend turning it off.
• Reminder to open Crane's port
• How to install.
  **Crane rpm is in the regular pulp repo on fedorapeople. Link to regular install docs for how to use it.
  • No default configuration file is provided. User must create one.
• How to run crane. Easy, the user doesn't have to, just restart httpd.
• Provide a working example. Sync and publish some repo, then show the full `docker pull` command including the exact path.