Add contribution metrics beyond commit count

[cuviper]

There are many ways to contribute that don't show up in commit counts. It would be nice if these were acknowledged too, although I don't know how well these can be tracked. Some ideas:

• Filing issues
• Opening pull requests (whether or not they ultimately get merged)
• Commenting on issues and pull requests
• Participating in discussions on either the users or internals forums
• Chatting in logged IRC channels (this may be too noisy)
• Third-party participation? stack overflow, reddit, etc.

[steveklabnik]

Yes, this would be cool. It requires a lot more API integration than we currently have, so it'd be a big step, but I'd like to see it as well.