feat: use sse to fetch new messages (close #70)

controller/message.go

@@ -185,11 +185,13 @@ func saveAndSendMessage(user *model.User, message *model.Message, channel_ *mode
 		if err != nil {
 			return err
 		}
+		go syncMessageToUser(message, user.Id)
 	} else {
 		if message.Async {
 			return errors.New("异步发送消息需要用户具备消息持久化的权限")
 		}
 		message.Link = "unsaved" // This is for user to identify whether the message is saved
+		go syncMessageToUser(message, user.Id)
 	}
 	if !message.Async {
 		err := channel.SendMessage(message, user, channel_)