add method for users to add books to library
Add method for user to create books with author, title, and description
Ahhhhh forgot to commit stuff!  So sorry. Add methods to create a due date, add a status to a book (available, checked out), check out a book and change the status to checked out, etc. LOSIN MAJOR POINTS HURR
Add logic to decide if a book is checked out or not based on when it is due
Add a method to mark a book as lost. Add logic to tell a user that a book is lost if they try to check out a lost book. Add a method to check if a book is overdue.
move all methods into library.rb, add main.rb for testing purposes