remove default Readme file
remove bought colum out of Product replace with aasm state
use aasm state for Product model
[r] use subject instead of user
the product should be sold after it is bought
create model to track clients who order the product
add aasm_state to white list
[b] not know the source of association
[b] public date still used in code
user would be in the order list of the product when the user click Buy on ui
use amazon s3 for paperclip storage