Added syntax highlighting to `README`

README.md

@@ -4,15 +4,19 @@ Silex, a simple Web Framework
 Silex is a simple web framework to develop simple websites based on
 [Symfony2][1] components:
 
-    require_once __DIR__.'/silex.phar';
 
-    $app = new Silex\Application();
+```php
+<?php
+require_once __DIR__.'/silex.phar';
 
-    $app->get('/hello/{name}', function ($name) {
+$app = new Silex\Application();
+
+$app->get('/hello/{name}', function ($name) {
   return "Hello $name";
-    });
+});
 
-    $app->run();
+$app->run();
+```
 
 Silex works with PHP 5.3.2 or later.