Pull in Tom's models and adjust.

manage.py syncdb now works, and pulls in all models listed in models.py

Also, models have been marked as unmanaged, so Django won't create/drop
tables.
Tweak validation: check HTTP method

Verify that HTTP method is what we think it is.  Creation should use
POST and update should use PUT.
Aesthetic change; no semantic difference

Use elif instead of if to clarify that only one branch will execute.
Tweak version tracking error messages