title: trying to install FOSUserBundle but getting error
body: <p>trying to install <strong>FOSUserBundle</strong> bundle from below link <a href="http://symfony.com/doc/current/cookbook/bundles/installation.html" rel="noreferrer">How to install 3rd party Bundles</a> but getting this error :</p>
  
  <pre><code>[Symfony\Component\Config\Definition\Exception\InvalidConfigurationException]  
    The child node "db_driver" at path "fos_user" must be configured. 
  </code></pre>