This is a video rental store program
it stores movie data into memory which is pointed to by various binary trees (pointer trees)
put together in a container called a "forest".  Each tree is sorted by a different field (title, genre,
number of rentals, etc)
Customers can add themselves to a waitlist if all copies of a movie is checked out, this uses a queue
structure, so it is first come, first serve.

the manager's password is "disco" but this can be changed once you log in as manager.