if user name is all empty, we assign a time flag for it.

eventSubscribe.go

@@ -101,8 +101,12 @@ func sendGreeting4ExistingUser(in InWechatMsg, info crmdLead) {
 
 func (m *WechatUserInfo) registerNewUserWithInfo(in InWechatMsg) (newuser crmdLead, err error) {
 	u := crmdLead{}
-	u.FirstName = "\u0020"
-	u.LastName = m.NickName
+	u.FirstName = "\u0020" //a visible space
+	if m.NickName == "" {
+		u.LastName = time.Now().Format(getCrmTimeLayout())
+	} else {
+		u.LastName = m.NickName
+	}
 	u.Password = "password"
 	u.WechatHitxyID = in.header.FromUserName
 	u.Status = "New"