run balance solution:
updating status of order( success -> fail or fail -> success)
there 3 steps :
1. change order status
2. update running balance
	When we change the order to fail, something goes wrong.    for example:   the merchant balance is zero.
3. insert into account history.
    We have to keep track of every change in the amount.
    for this mode: success -> fail
     So we must insert a record into the history table.
     due to the same order. we can't insert successfully.