/**
* Sets the sort property to the current sort value
*
* @param Model Model object subject of this observer method
*/
public function before_insert(Orm\Model $obj)
{
if ($obj instanceof SortableInterface) {
$max = $obj->getSortMax();
} else {
$max = $obj->query()->max($this->_property);
}
$obj->{$this->_property} = $max + $this->_offset;
}