Add tag module with post associations

src/main/java/com/openisle/model/Post.java

@@ -5,6 +5,11 @@ import lombok.Getter;
 import lombok.NoArgsConstructor;
 import lombok.Setter;
 
+import java.util.HashSet;
+import java.util.Set;
+
+import com.openisle.model.Tag;
+
 
 import java.time.LocalDateTime;
 
@@ -38,6 +43,12 @@ public class Post {
     @JoinColumn(name = "category_id")
     private Category category;
 
+    @ManyToMany(fetch = FetchType.LAZY)
+    @JoinTable(name = "post_tags",
+            joinColumns = @JoinColumn(name = "post_id"),
+            inverseJoinColumns = @JoinColumn(name = "tag_id"))
+    private java.util.Set<Tag> tags = new java.util.HashSet<>();
+
     @Column(nullable = false)
     private long views = 0;
 

src/main/java/com/openisle/model/Tag.java

@@ -0,0 +1,20 @@
+package com.openisle.model;
+
+import jakarta.persistence.*;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+@Entity
+@Getter
+@Setter
+@NoArgsConstructor
+@Table(name = "tags")
+public class Tag {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(nullable = false, unique = true)
+    private String name;
+}