如何使用MongoDB / Laravel / Jenssegers将其他类嵌入到另一个类中？

I am trying to do the following:

    $org = Organization::first();

    $user = Auth::user();

    $org->owner()->save($user);

    return $org;

My returned values are:

{"_id":"55f333759a370912040041c8",
"name":"Beta Productions",
"updated_at":"2015-09-11 20:03:01",
"created_at":"2015-09-11 20:03:01"}

If I try to return $org->owner, I don't get anything.

Here is my organization class:

<?php

namespace App;

use Jenssegers\Mongodb\Model as Model;

class Organization extends Model
{

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = ['name'];

    public function owner()
    {
        return $this->embedsOne('App\User');
    }
}

Any thoughts?