Test: use FactoryGirl

Since mongoid cannot work with fixtures, we need FactoryGirl, as she
is OK with anything, and especially mongoid. Notice that she creates
test objects and stores them straight into database before tests runs,
so we make small changes when testing creations of new objects.

Signed-off-by: Zeljko <zeljko@zwr.fi>
Model tests: seeding and the product

Signed-off-by: Zeljko <zeljko@zwr.fi>