Archived Prompts should be linked to relevant GitHub commits

[justuseapen]

This will make it easier to see how the code was altered in response to votes. This was actually voted on here:

http://www.selfgovern.us/prompts/6

But it seems a bit ambiguous. There is no law regarding this sort of problem. We could have another election or just build it and if it's voted down we'll get rid of it. Somehow I don't think that'll happen.