refactor: 리포지토리 계층 리팩토링 (DASOMBE-15)

Author: jucheonsu

src/main/java/dmu/dasom/api/domain/activity/repository/ActivityRepository.java

@@ -0,0 +1,8 @@
+package dmu.dasom.api.domain.activity.repository;
+
+import dmu.dasom.api.domain.activity.entity.Activity;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface ActivityRepository extends JpaRepository<Activity, Long> {
+
+}

src/main/java/dmu/dasom/api/domain/activity/repository/SectionRepository.java

@@ -0,0 +1,12 @@
+package dmu.dasom.api.domain.activity.repository;
+
+import dmu.dasom.api.domain.activity.entity.Section;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+import java.util.Optional;
+
+@Repository
+public interface SectionRepository extends JpaRepository<Section, Long> {
+    Optional<Section> findByName(String name);
+}