/**
* Create a new relation instance.
*
* @param LMongo\Eloquent\Builder
* @param LMongo\Eloquent\Model
* @return void
*/
public function __construct(Builder $query, Model $parent)
{
$this->query = $query;
$this->parent = $parent;
$this->related = $query->getModel();
$this->addConstraints();
}