feat: add point history

backend/src/main/java/com/openisle/model/PointHistory.java

@@ -0,0 +1,49 @@
+package com.openisle.model;
+
+import jakarta.persistence.*;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+import java.time.LocalDateTime;
+
+/** Point change history for a user. */
+@Entity
+@Getter
+@Setter
+@NoArgsConstructor
+@Table(name = "point_histories")
+public class PointHistory {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @ManyToOne(fetch = FetchType.LAZY, optional = false)
+    @JoinColumn(name = "user_id")
+    private User user;
+
+    @Enumerated(EnumType.STRING)
+    @Column(nullable = false)
+    private PointHistoryType type;
+
+    @Column(nullable = false)
+    private int amount;
+
+    @Column(nullable = false)
+    private int balance;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "post_id")
+    private Post post;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "comment_id")
+    private Comment comment;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "from_user_id")
+    private User fromUser;
+
+    @Column(name = "created_at", nullable = false)
+    private LocalDateTime createdAt;
+}