public function assign_rooms($id)
{
//get this retreat's information
$retreat = \montserrat\Retreat::with('retreatmasters', 'assistant', 'innkeeper', 'captains')->findOrFail($id);
$registrations = \montserrat\Registration::where('event_id', '=', $id)->with('retreatant.parish')->orderBy('register_date', 'DESC')->get();
$rooms = \montserrat\Room::orderby('name')->pluck('name', 'id');
$rooms->prepend('Unassigned', 0);
return view('retreats.assign_rooms', compact('retreat', 'registrations', 'rooms'));
}