config database connection
add Category class
add fields
add Item class
add fields
add CartItem class
add fields
add ItemDaoImpl
add getItems method
add getItem method
add insertItem method
add updateItem method
add delteItem method
modify itemDaoImpl
add test itemServiceImplTest
add tet should_return_itemList method
remove useless test
extract interface itemDao
extract interface itemService
modify getItems method