Feat: Post 기능 구현

* Feat: Post 기본 코드 구현
- 깃허브가 꼬여서 이전에 작성한거 다시 가지고 왔습니다..

* Fix: Post - Member Id 외래키 매핑

* Fix: Post - @NotNull 적용

src/main/java/notai/post/application/PostQueryService.java

@@ -0,0 +1,4 @@
+package notai.post.application;
+
+public class PostQueryService {
+}

src/main/java/notai/post/application/PostService.java

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+package notai.post.application;
+
+public class PostService {
+}

src/main/java/notai/post/domain/Post.java

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+package notai.post.domain;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.ManyToOne;
+import jakarta.validation.constraints.NotNull;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import notai.member.domain.Member;
+
+import static jakarta.persistence.GenerationType.IDENTITY;
+import static lombok.AccessLevel.PROTECTED;
+
+@Getter
+@NoArgsConstructor(access = PROTECTED)
+@AllArgsConstructor
+@Entity
+public class Post {
+    @Id
+    @GeneratedValue(strategy = IDENTITY)
+    private Long id;
+    @ManyToOne
+    @NotNull
+    @JoinColumn(name="member_id")
+    private Member member;
+    @NotNull
+    @Column(length = 255)
+    private String title;
+    @NotNull
+    @Column(length = 255)
+    private String contents;
+
+    public Post(
+            Member member,
+            String title,
+            String contents
+    ) {
+        this.member = member;
+        this.title = title;
+        this.contents = contents;
+    }
+}

src/main/java/notai/post/domain/PostRepository.java

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+package notai.post.domain;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface PostRepository extends JpaRepository<Post, Long> {
+
+}

src/main/java/notai/post/presentation/PostController.java

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+package notai.post.presentation;
+
+public class PostController {
+}