[DB] 디비 설계 참고

https://yeongunheo.tistory.com/entry/DB-%EC%84%A4%EA%B3%84%ED%95%98%EB%8A%94-%EB%B2%95-feat-%EB%8D%B0%EC%9D%B4%ED%84%B0-%EB%AA%A8%EB%8D%B8%EB%A7%81