add class MockStudentServiceImpl

src/main/java/id/ac/ui/tutorial0/service/MockStudentServiceImpl.java

+package id.ac.ui.tutorial0.service;
+
+
+import id.ac.ui.tutorial0.model.Student;
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+
+@Service
+public class MockStudentServiceImpl implements StudentService{
+
+    @Override
+    public Student create(Student student) {
+        return null;
+    }
+
+    @Override
+    public List<Student> findAll() {
+        return null;
+    }
+}
\ No newline at end of file