add fetch demo

Author: rwifeng

demos/fetch.php

@@ -0,0 +1,25 @@
+<?php
+require_once '../vendor/autoload.php';
+
+use Qiniu\Auth;
+use Qiniu\Storage\BucketManager;
+
+$accessKey = 'XI0n2kV1LYwzcxqSZQxJ7bpycxDIAXFGJMWUt_zG';
+$secretKey = '9WTmIAiwKQ2Nq6o93mfKd6VQqq56HjjLZonMWLJl';
+
+$auth = new Auth($accessKey, $secretKey);
+$bmgr = new BucketManager($auth);
+
+$url = 'http://php.net/favicon.ico';
+$bucket = 'rwxf';
+$key = time() . '.ico';
+
+list($ret, $err) = $bmgr->fetch($url, $bucket, $key);
+echo "fetch $url to bucket: $bucket  key: $key\n";
+if ($err !== null) 
+{
+	var_dump($err);
+} else {
+	var_dump($ret);
+}
+