Django app (mostly for the ORM) to store historical NextBus data.

The eventual goal is to be able to answer questions like:
* How much of the time does NextBus have data?
* How closely does actual bus performance match scheduled bus performance?
* How closely does NextBus's predictions (like ten minutes before the bus
  arrives) match with actual arrival times (as measured by when NextBus
  prediction goes from near zero to high, or by non-NextBus data)?

The idea is just to store All The Data and make it available, and do analysis
offline.