Log chat in mongo (feedback requested)

I need feedback.

The goal of this is to log chat. It currently has no mechanism for limiting the number of lines it stores. Each chat line is stored in MongoDB as a BotRequest struct (serialized automatically?).

I have been trying to figure out how to do a query on it, but while I can do a query in Mongo, I can't seem to use mgo to get any result.

I plan to clean up and squash all the commits eventually. For #14