adding php files for second exercise

src/02-shipping/docroot/plainHttpService.php

@@ -0,0 +1,11 @@
+<?php
+    //  shipping.php contains our get_shipping_options($zipcode, $pounds) function.
+    //  It returns an array mapping service name to price in US dollars.
+    require ('shipping.php');
+
+    $options = get_shipping_options($_REQUEST[zipcode], $_REQUEST[pounds]);
+    foreach ($options as $service => $price) {
+        $result[] = "$service: $price USD";
+    }
+    print implode("\n", $result);
+?>