library.rb

class Library
  attr_accessor :books
  
  def initialize
    @books = []
  end
  
  def add_book(title, author)
    @books << Book.new(title, author)
  end
  
  def suggest_a_book
    p "Why not pick up #{books.sample.title}?"
  end
  
  def suggest_an_author
    p "How about reading something by #{books.sample.author}?"
  end
end