public function setRealName($real_name): User
    {
        if ($this->real_name !== $real_name) {
            $this->real_name = $real_name;

            DB::table('user')
                ->where('user_id', '=', $this->user_id)
                ->update([
                    'real_name' => $real_name,
                ]);
        }

        return $this;
    }