Command for auto-configuring a repo

[huonw]

E.g.

$ homu-add --help
Usage: homu-add user/repo [--reviewer NAME] [--travis [TOKEN]]

Add `github.com/user/repo` to this instance of homu.

Options:
    -r, --reviewer NAME
         Add NAME as a reviewer. If `user` is a user, they are included by 
         default. Can be specified several times.
    --travis [TOKEN]
         Include support for running tests on travis. Tries to infer TOKEN
         from other `[repo.*.travis.token]`'s if not specified.

This would be great if it could add the necessary web-hooks (would presumably require specifying a domain/IP as well as a port?), and even better if it could (optionally) add the Travis configuration to the .travis.yml.

[Gankra]

CC @reem @brson @alexcrichton

[Gankra]

As a more elaborate project it would be cool if we had a tool that basically handled the standard boiler-plate of setting up all of travis/docs/homu/whatever automation. There's a patchwork of guides, and to my knowledge most of it is total boiler-plate that can be automated.