title: Symfony2 extend ACL with additional Permissions
body: <p>I want to implement the Symfony2 ACL into my project. The basic permissions (VIEW, EDIT...) are however not sufficient for me. I would need at least two additional permissions, namely COPY and REVIEW. </p>
  
  <p>After some digging around, I found that I will mostly likely have to overwrite/extend <code>Symfony/Component/Security/Acl/Permission/BasicPermissionMap.php</code> and <code>Symfony/Component/Security/Acl/Permission/MaskBuilder.php</code>. </p>
  
  <p>In <code>Symfony/Bundle/SecurityBundle/Resources/config/security_acl.xml</code> I found a line that refers to the permission map: </p>
  
  <pre><code>&lt;parameter key="security.acl.permission.map.class"&gt;Symfony\Component\Security\Acl\Permission\BasicPermissionMap&lt;/parameter&gt;
  </code></pre>
  
  <p>I tried overwriting this in <code>app/config/config.yml</code>, but that didn't work (I got an error that the permission config key was unknown, or something like that). </p>
  
  <p>I've been looking at the services as well, by using <code>app/console container:debug</code>, but I couldn't find any relevant service to overwrite there either. </p>
  
  <p>Could someone point me in the correct direction? </p>