Updated README.md

Author: creocoder

README.md

@@ -14,7 +14,7 @@ The preferred way to install this extension is through [composer](http://getcomp
 Either run
 
 ```bash
-$ php composer.phar require creocoder/yii2-nested-sets
+$ composer require creocoder/yii2-nested-sets
 ```
 
 or add