참고: 1차 https://kingofbackend.tistory.com/172 https://velog.io/@jhoon12/%EB%82%98%EB%A7%8C%EC%9D%98-%EC%B1%84%ED%8C%85-%EC%84%9C%EB%B9%84%EC%8A%A4-%EB%A7%8C%EB%93%A4%EA%B8%B0react-express-Socketio 2차 https://gslabs.tistory.com/93 https://github.com/feathersjs/feathers/issues/1149