README : update composer install method

README.md

@@ -21,3 +21,15 @@ Create a composer.json file with content :
     }
 }
 ```
+
+Install the last version : `composer install`
+
+Then use it :
+```php
+<?php
+
+require_once ("vendor/autoload.php");
+
+$version = new Domframework\Version();
+var_dump($version::version());
+```