Testimonial workflow, model, and UI

At some point we want a way for logged-in users to offer a testimonial. That is a textual blurb which says something positive about their experience with Boost. The testimonial will be a text field in the database record for the user. Once they create a testimonial the only thing they can do after that is to edit the testimonial or delete it.

New or changed testimonials go into a moderation queue (if they are changed, the old one is shown or taken down until the new one is approved).

There will be some kind of UI for showing a random testimonial or a testimonial of the day or something. This will probably go on the home page.