增加字段注释

model/ladder_price_request.go

@@ -12,7 +12,7 @@ type LadderPriceRequest struct {
 
 	GoodsId  string `json:"goods_id" form:"goods_id" binding:"required" required_errcode:"104004"`
 	Num  int64 `json:"num" form:"num" binding:"required" required_errcode:"104005"`
-	Currency int    `json:"currency" form:"currency" binding:"required" required_errcode:"104006"`
+	Currency int    `json:"currency" form:"currency" binding:"required" required_errcode:"104006"`//币种 1人民币 2美元
 	Costly  int    `json:"costly" form:"costly" `//暂时不知道是什么意思
 }