Add a failing test for Topping.initialize.
Add failing test for vegetarian toppings.
Pass "sets the name of the topping" test.
Pass vegetarian test.
Add failing test 'records all of the toppings'.
And Pizza class initializer.
Add new test for Pizza class: "it defaults the toppings to cheese only...
if the pizza has no toppings'
Move Pizza class to be below topping class.  Pizza now calls a default
toping of cheese as the default topping and passes the test.
Add pry-debugger to required libraries.