Add title and id method to Book
Add default status of book instance
Add check_out method
Add cannot check out twice
Add check in method to Book class
Add name method to class Borrower
Default of zero books for new Library instance
Assign SecureRandom id to new books in Library
Allow check out with book id
Access to who borrowed a book
Add cannot borrow twice check
Add check-in method
Add borrow limit at 2 books
Return available books
Return borrowed books