Track communities with multiple repos

[sagesharp]

Suggested by @mjgiarlo.

Many communities have separate repositories for code and documentation. It would be good to combine statistics across those repositories.

Other communities are really separate sub-communities that share the same repository (e.g. the Linux kernel). Some, like OpenStack, have sub-communities split across multiple repositories.

Basically, this is a hard problem, and I want to allow people flexibility in what repos they want to study. I'll have to give this one more thought.

[mjgiarlo]

A concrete use case I have for the Hydra community is that I'd like to point the scraper at one or more GitHub orgs at the same time. An initial target would be the ability to harvest from all repos in a single organization. You could make the repo arg optional, and if it's not supplied, the scraper would get a list of all repos in an org and then loop over them all in turn.

Thanks, @sarahsharp