Add missing migrations for small changes in DB schema
Add missing migrations for small changes in DB schema

* on_delete behavior for Award.event,
* ordering for Lesson

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