Feat: 서비스 트랜잭션 설정

Author: joyewon0705

src/main/java/com/back/domain/user/service/UserService.java

@@ -10,9 +10,11 @@
 import lombok.RequiredArgsConstructor;
 import org.springframework.security.crypto.password.PasswordEncoder;
 import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
 
 @Service
 @RequiredArgsConstructor
+@Transactional
 public class UserService {
     private final UserRepository userRepository;
     private final PasswordEncoder passwordEncoder;