offering_creation

-[X]generate offering_creation model
-[X]migrated
-[X] establishing "Creator-Act" association for event
-[X]User Model
-[X]Event Model
-[X]OfferingCreation Model
-[X]initial test
-[X]user should respond to events_created
-[X]event should respond to creator
-[ ]user and event should respond to offering_creations