feat(dao): add initial data access object templates

src/main/java/dev/dao/OrderDao.java

@@ -0,0 +1,25 @@
+package dev.dao;
+
+import dev.model.Order;
+
+import java.util.List;
+
+public class OrderDao {
+
+    public int save(Order order) {
+
+        // TODO:
+        // Insert order and return generated id
+
+        return -1;
+    }
+
+    public List<Order> findByUserId(int userId) {
+
+        // TODO:
+        // Retrieve all orders of a user
+
+        return null;
+    }
+
+}