update schema.rb
update TODO
update TODO list for homework v2
user can delete product from cart
user can choose number of products before add it to cart
user can choose number of products before add it to cart (missing files)
add quantity for each prodcut in cart
correct total price of cart
user can't add product with 0 quantity into cart
1. User can get correct quantity on order page.
2. Delete cart after payment.
user can check order history at account/orders
after pay order, redirect to account/orders
1. As a admin, he can see all orders at admin/orders
2. As a admin, he can translate order state at admin/orders#show and
should follow the rule of state machine.
format the html files and add div of container class in some views
add TODO item