Add a new interface to be implemented by things that can add events to the database
Hm, the product ID is really associated with the session (you can't have a single session with events for more than one product)
Modify the generated query to use the new data structure
First pass at an implementation for the 'start session' action
Factor out methods for looking up products & users. Product/organization is implied by session ID. Initial work on the code to add an event.
Add a TODO for a fairly dumb design error
Create a 'test' user with an identifier that we always know about.