movies/app/Models/MediaList.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class MediaList extends Model
{
    public const WATCHLIST = 'Watchlist';
    public const COLLECTION = 'Collection';
    public const WATCHED = 'Watched';
    public const LIKED = 'Liked';

    public const SPECIAL_LISTS = [
        self::WATCHLIST,
        self::COLLECTION,
        self::WATCHED,
        self::LIKED,
    ];

    protected $fillable = [
        'description',
        'favorites_count',
        'tmdb_id',
        'item_count',
        'iso_639_1',
        'iso_3166_1',
        'list_type',
        'name',
        'slug',
        'poster_path',
        'user_id',
        'public',
    ];

    public function user()
    {
        return $this->belongsTo(User::class);
    }
}