multi-select forms on creation - throws DoesNotExist

[jwhaney]

does not only occur when creating a new collection, but also new training record for tnris.org and possibly other forms.

details:
when you create a new training record, and you select from the instructors multi-select input while creating that new record, a DoesNotExist error is thrown on save because the training record does not exist yet and the functions in forms.py try to use both the domain table and the training table instances at the same time.