In case you want to use the full apps repo within your ownCloud installation (most probably for development)
  you can follow these steps:
  
  1. clone this repo into your ownCloud installation into a new folder (maybe called apps2):
     git clone git@github.com:owncloud/apps.git apps2
  
  2. add this additional apps folder to your configuration (config/config.php):
    'apps_paths' =>
    array (
      0 =>
      array (
        'path' => OC::$SERVERROOT.'/apps',
        'url' => '/apps',
        'writable' => false,
      ),
      1 =>
      array (
        'path' => OC::$SERVERROOT.'/apps2',
        'url' => '/apps2',
        'writable' => false,
      )
      ),
  
  3. Done ;-)