Fix missing import (django.db.Model) in views
Fix missing import (django.db.Model) in views

This fixes NameError exception "global name 'Model' is not defined".
Exception occured in `CreateViewContext` class-based view.

This must have been my fault when I introduced `CreateViewContext` class
view.

vahtras/amy,wking/swc-amy,swcarpentry/amy,wking/swc-amy,shapiromatron/amy,swcarpentry/amy,swcarpentry/amy,wking/swc-amy,pbanaszkiewicz/amy,shapiromatron/amy,shapiromatron/amy,vahtras/amy,pbanaszkiewicz/amy,vahtras/amy,wking/swc-amy,pbanaszkiewicz/amy