export function loadLoginInfo(user_id: number, server: number, callbackFn?: (err: MongoError, doc: IUserDocument) => void) {
    return userModel.findOneAndUpdate({ user_id }, { last_update: new Date(), game_server: server })
      .select("-password -client_token -join_date")
      .populate("earnings", "-user_id -_id")
      .populate("relationship", "rank photo_url photo_privacy gender fb_id game_id")
      .lean().exec(callbackFn);
  }