add api

src/main/java/com/example/template/OrderRepository.java

@@ -2,7 +2,10 @@ package com.example.template;
 
 import org.springframework.data.repository.PagingAndSortingRepository;
 
+import java.util.List;
+
 public interface OrderRepository extends PagingAndSortingRepository<Order, Long> {
 
+    List<Order> findByCustomerId(String customerId);
 }