[fix]:#142 파일추가

src/main/java/ussum/homepage/domain/post/service/PostAdditionalReader.java

@@ -0,0 +1,21 @@
+package ussum.homepage.domain.post.service;
+
+import jakarta.transaction.Transactional;
+import java.util.List;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import ussum.homepage.domain.post.Post;
+import ussum.homepage.domain.post.RightsDetail;
+import ussum.homepage.domain.post.RightsDetailRepository;
+
+@Service
+@RequiredArgsConstructor
+public class PostAdditionalReader {
+    private final RightsDetailRepository rightsDetailRepository;
+
+    @Transactional
+    public List<RightsDetail> getRightsDetailByPostId(Long postId) {
+        List<RightsDetail> rightsDetails = rightsDetailRepository.findAllByPostId(postId);
+        return rightsDetails;
+    }
+}