feat(UserService) : 컨트롤러에서 갖고있던 로직을 서비스로 분리

#15

src/main/java/client/service/UserService.java

@@ -0,0 +1,27 @@
+package client.service;
+
+import client.controller.dto.CreatUserDto;
+import client.model.User;
+import client.repsotiroy.UserRepository;
+import spring.mvc.annotation.Service;
+
+import java.util.List;
+
+@Service
+public class UserService {
+    private final UserRepository userRepository;
+
+    public UserService(final UserRepository userRepository) {
+        this.userRepository = userRepository;
+    }
+
+    public User createUser(final CreatUserDto creatUserDto) {
+        User user = User.from(creatUserDto);
+        userRepository.save(user);
+        return user;
+    }
+
+    public List<User> getUsersWithSize(final int wannaSize) {
+        return userRepository.getUsersWithLimit(wannaSize);
+    }
+}