defining a relationship

mapping.php

<?php
namespace API\Service\Command;

use API\Service\CommandService;

class ContentCommandService extends CommandService
{
    protected $hasMany = 'Asset';
    protected $uses = 'ContentMapping';

    public function create(array $params, $userId = false) {
        $id = parent::create($params, $userId);
        return $id;
    }

    public function modify($id, array $params, $userId = false) {
        $id = parent::modify($id, $params, $userId);
        return $id;
    }

    public function remove($id, $userId = false) {
        $success = parent::remove($id, $userId);
        return $success;
    }
}