Use UTC timezone to refund orders

The order deadline is stored in UTC but we were comparing it to the
local timezone to decide if we need to close it.

* Closes: #27

api/db/order.go

@@ -386,7 +386,7 @@ func updateOrderPurchase(tx *gorm.DB, memberNum int, transaction *Transaction, t
 
 func (d *DB) DeactivateOrders() []Order {
 	var orders []Order
-	now := time.Now()
+	now := time.Now().UTC()
 	err := d.db.Where("active = ? AND deadline < ?", true, now).
 		Preload("Member").
 		Preload("Transactions.OrderPurchase.OrderProduct.Product").