Refactor git commands into separate files

[calebhearth]

I believe I remember seeing in one of the issues here (no citation, sorry) that there is some interest in splitting lib/hub/commands.rb into separate files for each of the commands.

I thought I might take a whack at that, but I don't want to put a bunch of effort into it if there is no longer any interest.

If I were to do the legwork to pull everything out - making sure that the tests still pass of course, would that potentially be an accepted pull-request?

Additionally, are there any particular difficulties that have prevented this from happening up to now?

[mislav]

It's a bigger effort than you think. It was suggested in #39. However, to be clear, we aren't talking about simply splitting one big Ruby file into multiple smaller ones. We wanted to split one executable out to multiple hub-* executables, a la git.

Yes, I would like commands to be split, especially the hub-specific commands such as fork and pull-request.

1. The Runner would have to be refactored slightly to support this new scheme. This isn't a big effort.
2. Each separate script would have to require helper methods again (context.rb, github_api.rb, ...) because it would run as a separate process than hub executable, just as git clone command spawns a separate process for git-clone.
3. Such split would make it impossible to generate a single standalone executable as we do now. We would have to abandon the standalone install process, which is currently the most conventient install strategy (after Homebrew).
4. We wouldn't gain much with this split, except easier maintenance of the codebase. The performance of hub would actually degrade slightly.

Closing this because it's a dup of #39.