GET /topic/%23%E6%9D%B1%E4%BA%AC%E4%BA%94%E8%BC%AA%E3%81%AE%E5%8D%B3%E6%99%82%E4%B8%AD%E6%AD%A2%E3%82%92%E6%B1%82%E3%82%81%E3%81%BE%E3%81%99