add discout default to#add_menu_item and MenuItem#initialize
begin test to check menu_item discount default
create test to check a menu_item default discount value
use binding.pry to test
modify Bar#get_price to only allow drinks with discount status of true to receive happy hour discounts
create test to order and keep track of a drink
separate order and track drink to order drink test and log drink order frequency test
create Bar#purchase_drink method that logs a drink purchase along with price
change log drink test to check only log drinks ordered.  Will add frequency test later
modify @drinks_ordered from hash to array.  Bar#purchase_drink now pushes drink ordered and price to @drinks_ordered array
work in progress to calculate top selling drinks
modify #purchase_drink
modify test for most popular drinks