Define directories that users of this profile can access.
    * Use alphanumeric characters as directory paths.
    * To specify file system root, just enter .(dot) character.
    * Use %uid as a placeholder for user ID. Ex: users/user%uid creates directories such as users/user1, users/user42, etc.
    * To remove a directory from the list, leave the directory path blank.
    * If you want more flexibility in directory paths you can execute php to return a directory path.
      For php execution your directory path must start with php: and the rest must be a valid php code that is expected to return the actual directory path.
      Ex: php: return 'users/'.$user->name; defines users/USER-NAME as the directory path.
      A multi-level directory example php: return date('Y', $user->created).'/'.date('m', $user->created).'/'.$user->uid; defines MEMBERSHIP-YEAR/MONTH/USER-ID as the directory path, resulting in self-categorized user directories based on membership date.
      Note that you should use the $user variable instead of $GLOBALS['user'] since they are not always the same object.