fix mongoDB bug

internal/api/manage/management_chat.go

@@ -475,6 +475,10 @@ type FileElem struct {
 type AtElem struct {
 	Text        string   `mapstructure:"text"`
 	AtUserList  []string `mapstructure:"atUserList"`
+	AtUsersInfo []struct {
+		AtUserID      string `json:"atUserID,omitempty"`
+		GroupNickname string `json:"groupNickname,omitempty"`
+	} `json:"atUsersInfo,omitempty"`
 	IsAtSelf bool `mapstructure:"isAtSelf"`
 }
 type LocationElem struct {