Coin

1. user_coin

1.1. id

1.2. user_id

1.3. coin

2. user_coin_transaction

2.1. id

2.2. user_coin_id

2.3. order_id

2.4. quantity_coin_transaction

2.5. coin_transaction_type

2.5.1. 0: buy (add to user_coin)

2.5.2. 1: buy (using coin to buy products, minus from user_coin)

2.5.3. 2: change to money (id_order = 0, minus from user_coin)

2.6. create_date