created method to return a book's title, author; created method to add books to the Library's @books array; created method to list each book in the library, but it does not yet list the book's status
Commiting before merging with Mike's code
added method borrow_book for the Borrower class; created books array for each instance of the Borrower class that adds book items when the method borrow_book is called; created check_out method
created method borrowed_books_list
created method borrowed_books for the Library class
created method available_books for the Library class
replaced some methods with attr_reader/attr_accessor; added option to assign books an edition and/or publication year
added method check_in to the Library class to allow users to return a book, rate the returned book; added  method avg_rating to the Book class to check average rating of each book
added the ability for a user to give a book a review when they check_in the book; added method add_review for the Book class; added method; added method reviews_list for the Book class
Wrote in code documentation according to TomDoc specifications for methods that I had added.