
$resource = $client->getResource('/images/JRLogo');
$joeuser = $client->getUsers('joeuser');
$perms = $client->getPermissions($resource->getUriString());

$perm = new Permission('1', $joeuser[0], $resource->getUriString());
$perms[] = $perm;

$client->updatePermissions($resource->getUriString(), $perms);
