Automatically add debt to users who are added to a show later

[mickzijdel]

Pro

• Less work for the Front of House-manager
• Less people who should be in debt but never received their debt.

Cons

• Requires a minor overhaul of the debt adding system, though not a big one. (Store the amount of debts per person along with the debt due date)
• Gives debt to people who might be accidentally added to a show (but how often does that happen? I’ve seen shows with half of the team and none of the cast added when I was FOH, but never a show with people who should not be there. It can also always be forgiven.) (Should probably be something that it only happens for shows this academic year or something so we do not generate a lot of debts for people who left years ago)