give attributes title, author, and id
Added status as 'available'
add checked_out method
return true for 'check_out'
Add inability to check out twice
Add check_in fuction
give borrower name attribute
Initialize library with empty array
Create new book and assign ID
Allow book to be borrowed
knows who borrowed a book
Book can only be checked out once at a time
Borrower can only check out two books
Show available books
returns borrowed books
Final commit