fix 公告

@@ -92,7 +92,7 @@ type UpdateBulletinRequest struct {
 	AllowClose int    `json:"allow_close"`
 	//AllowCondition int      `json:"allow_condition"`
 	QuestionSwitch int      `json:"question_switch"`
-	Receiver       []string `json:"receiver" valid:"Required"`
+	Receiver       []VisibleObject `json:"receiver" valid:"Required"`
 	Question       Question `json:"question"`
 	Cover          Cover    `json:"cover" valid:"Required"`
 }