model.define():
https://sequelize.org/docs/v6/core-concepts/model-basics/
foreign key:
https://velog.io/@mong-head/Node-Sequelize-foreign-key-설정
https://bubobubo003.tistory.com/39
raw query:
https://sequelize.org/docs/v6/core-concepts/raw-queries/
fs module file:
https://nodejs.org/api/fs.html#fsexistspath-callback
formData
https://velog.io/@sa833591/form-data-그리고-MultipartFile
애증의 join
https://kimsyoung.tistory.com/entry/3개-이상의-테이블-LEFT-JOIN-하기
data type
https://sequelize.org/docs/v7/other-topics/other-data-types/