新增盟主时记录最新购买时间

AppStart/Helper/AlipayPayBack2Service.cs

@@ -1170,6 +1170,7 @@ namespace MySystem
                     CreateDate = DateTime.Now, //设置时间
                     UserId = UserId, //用户
                     LeaderLevel = LeaderLevel,
+                    LastBuyDate = DateTime.Now,
                     ExpiredDate = DateTime.Now.AddMonths(Month),
                 });
             }