Add Bar.initialize with name param
Add menu_items array and attr_accessor method
Add add_menu_item method
Add MenuItem class with getter methods
Add happy_discount attr_accessor to class Bar
Modify happy_discount to change depending on happy hour
Modify happy_discount setter so discount can't be more than 1 or less than 0
Modify happy_hour? method and add passing test
Add test for discount not applying after happy_hour and applying for happy hour