Import and add products for Order and calculate ShoppingCart total cost
put product file(for example products.json) at directory '/data'
run ruby cli.rb
run rspec for test
help -- list all commands available
exit/quit -- exit CLI
import -- import products from json file, example: import products.json
show products -- list all products available
add item -- add single item to ShoppingCart by uuid, example: add item 1411
show shoppingcart -- show current order, including items and total cost of the ShoppingCart