Kotlin-Server-Side-Lab 🙄👻 브랜치 확인 -> !! branch: 1.Simple_Post_CRUD_API [SpringBoot + Kotlin + JPA] 간단한 게시글 CRUD REST Api 구현. branch: 2.SlackPush [Springboot + Kotlin + JPA] Slack 채널 메세지 전송 연동. branch: 3.Kotest branch: 4.Exception Handling [Springboot + Kotlin + JPA] Exception Handling by Kotlin branch: 5.RelationShips [Kotlin + Springboot + JPA] Entity 연관관계 (지연로딩, OrphanRemoval 확인) by Kotlin