Admin: data integrity

[charliemarlow]

We need to make sure that all admin operations are valid.

I.e. an admin cannot delete a movie if there are active bookings (potentially there would need to be a refund), or delete showrooms that have showtime.

[charliemarlow]

This is implemented for everything except for manage users, manage admin

[charliemarlow]

this is done for manage users

[charliemarlow]

need to have a discussion on rules for deleting objects and invalidating objects after a period of time

[charliemarlow]

Deleting a movie:

• if no showtimes in the future: then delete it

Deleting a Showtime:

• no bookings

Deleting a Theater:

• no future showtimes

Deleting a Promotion:

• remove ones that are valid until

Deleting a Customer:

• no active bookings
• FIXED