add booking flow

src/main/kotlin/com/android/trisolarisserver/models/room/RoomStayChange.kt

@@ -0,0 +1,36 @@
+package com.android.trisolarisserver.models.room
+
+import com.android.trisolarisserver.models.property.Property
+import jakarta.persistence.*
+import java.time.OffsetDateTime
+import java.util.UUID
+
+@Entity
+@Table(
+    name = "room_stay_change",
+    uniqueConstraints = [UniqueConstraint(columnNames = ["room_stay_id", "idempotency_key"])]
+)
+class RoomStayChange(
+    @Id
+    @GeneratedValue
+    @Column(columnDefinition = "uuid")
+    val id: UUID? = null,
+
+    @ManyToOne(fetch = FetchType.LAZY, optional = false)
+    @JoinColumn(name = "property_id", nullable = false)
+    var property: Property,
+
+    @ManyToOne(fetch = FetchType.LAZY, optional = false)
+    @JoinColumn(name = "room_stay_id", nullable = false)
+    var roomStay: RoomStay,
+
+    @ManyToOne(fetch = FetchType.LAZY, optional = false)
+    @JoinColumn(name = "new_room_stay_id", nullable = false)
+    var newRoomStay: RoomStay,
+
+    @Column(name = "idempotency_key", nullable = false)
+    var idempotencyKey: String,
+
+    @Column(name = "created_at", nullable = false, columnDefinition = "timestamptz")
+    val createdAt: OffsetDateTime = OffsetDateTime.now()
+)