重构白银节点分配方式，使用手动接口精确配置节点

web/models/bill.go

@@ -18,10 +18,10 @@ type Bill struct {
 	Type       BillType        `json:"type" gorm:"column:type"`               // 账单类型：1-消费，2-退款，3-充值
 	Amount     decimal.Decimal `json:"amount" gorm:"column:amount"`           // 账单金额
 
-	User     *User     `json:"user" gorm:"foreignKey:UserID"`
-	Trade    *Trade    `json:"trade" gorm:"foreignKey:TradeID"`
-	Resource *Resource `json:"resource" gorm:"foreignKey:ResourceID"`
-	Refund   *Refund   `json:"refund" gorm:"foreignKey:RefundID"`
+	User     *User     `json:"user,omitempty" gorm:"foreignKey:UserID"`
+	Trade    *Trade    `json:"trade,omitempty" gorm:"foreignKey:TradeID"`
+	Resource *Resource `json:"resource,omitempty" gorm:"foreignKey:ResourceID"`
+	Refund   *Refund   `json:"refund,omitempty" gorm:"foreignKey:RefundID"`
 }
 
 // BillType 账单类型枚举