some memoization to prevent duplicate queries
substract two scopes instead of an array and a scope
use eql and eq in specs instead of ==
positive testcase for chronological order of starts_at/ends_at of reservation
better names for checking availability of a reservation
getting rid of sql in controllers
dont test the limiting to 100 reservations
use a scope instead of casting to an array straight away
use current scope in rake task, so we won't try to start reservations
that should have ended already
cleanup
cleanup