modify CartService bean
modify CartServiceTest
add toString method
create CategoryRowMapper class
finish CategoryRowMapper
delete useless codes
finish Printer class
delete useless bean
create PromotionRowMapper class
finish class
delete useless codes
create ItemRowMapper class
finish method of ItemRowMapper
delete useless codes
clean up import
delete useless codes
create bean of ItemService
create bean of PromotionService
create Scanner bean
finish creation of beans