Completed, I think

[jonahroth]

@kmodlich @maxdignan I changed one line of the "don't change" part because otherwise the associations kept getting stored as nil, and that one change (storing an id instead of the entire object) makes the code much more understandable without significantly changing what it does

[maxdignan]

This is one of the more challenging tasks on PairColumbus, but it looks like this is a solid solution.

[mikegee]

I'm pretty sure you don't need to map the rooms to their ids. ActiveRecord probably handles this the same:

Booking.where(:room => rooms)

Better yet, let ActiveRecord handle the whole thing:

has_many :bookings, through: :rooms