feat: Auditing 및 Persist 설정이 담긴 BaseEntity 추가

src/main/kotlin/roomescape/RoomescapeApplication.kt

@@ -3,7 +3,9 @@ package roomescape
 import org.springframework.boot.Banner
 import org.springframework.boot.SpringApplication
 import org.springframework.boot.autoconfigure.SpringBootApplication
+import org.springframework.data.jpa.repository.config.EnableJpaAuditing
 
+@EnableJpaAuditing
 @SpringBootApplication
 class RoomescapeApplication
 

src/main/kotlin/roomescape/common/entity/BaseEntity.kt

@@ -0,0 +1,35 @@
+package roomescape.common.entity
+
+import jakarta.persistence.*
+import org.springframework.data.annotation.CreatedDate
+import org.springframework.data.annotation.LastModifiedDate
+import org.springframework.data.domain.Persistable
+import org.springframework.data.jpa.domain.support.AuditingEntityListener
+import java.time.LocalDateTime
+import kotlin.jvm.Transient
+
+@MappedSuperclass
+@EntityListeners(AuditingEntityListener::class)
+abstract class BaseEntity(
+    @Column(updatable = false)
+    @CreatedDate
+    var createdAt: LocalDateTime? = null,
+
+    @LastModifiedDate
+    var lastModifiedAt: LocalDateTime? = null,
+) : Persistable<Long> {
+
+    @Transient
+    private var isNewEntity: Boolean = true
+
+    @PostLoad
+    @PostPersist
+    fun markNotNew() {
+        isNewEntity = false
+    }
+
+    override fun isNew(): Boolean = isNewEntity
+
+    abstract override fun getId(): Long?
+
+}