https://github.com/Library-solider/codesquad-library/blob/master/src/main/java/com/librarycodesquad/prod/global/error/ErrorCode.java https://velog.io/@backtony/Spring-REST-Docs-์ ์ฉ-๋ฐ-์ต์ ํ-ํ๊ธฐ https://github.com/backtony/blog-code/blob/master/spring-rest-docs/src/test/resources/org/springframework/restdocs/templates/custom-response-fields.snippet https://github.com/kascu/kascu-backend/pull/9