[add]カテゴリーのEntityとRepositoryを追加

src/main/java/com/example/demo/entity/BookCategory.java

@@ -0,0 +1,22 @@
+package com.example.demo.entity;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.Id;
+import jakarta.persistence.Table;
+
+import lombok.Data;
+
+@Entity
+@Data
+@Table(name="book_category")
+public class BookCategory {
+
+
+    @Id
+    @Column(name = "book_category_id")
+    private Integer bookCategoryId;
+
+    @Column(name = "book_category_name")
+    private String bookCategoryName;
+}

src/main/java/com/example/demo/repository/BookCategoryRepository.java

@@ -0,0 +1,10 @@
+package com.example.demo.repository;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+
+import com.example.demo.entity.BookCategory;
+
+public interface BookCategoryRepository
+        extends JpaRepository<BookCategory,Integer> {
+
+}