add coupon filed on orders table.

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>
update default coupon value.

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>
support coupon filed for adding order.

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>
support get user phone coupon.

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>