Document describing Grok development process

We need a document describing to developers interested in extending the Grok core or writing Grok extensions what the process is. This is especially important for the core. What would someone need to do to add something to the Grok core? It doesn't need to be very formal (in fact shouldn't be), but it might include discussing it on the mailing list (or putting summaries of irc conversations there, to keep others in the loop), and posting new issues on launchpad.