test/app/Http/Models/SitePayment.php

<?php

namespace App\Http\Models;

use Illuminate\Database\Eloquent\Model;

class SitePayment extends Model
{
    protected $table = 'sites_payment';
    protected $primaryKey = 'site_id';
    public $incrementing = false;
    protected $casts = [
        'google_bid' => 'array'
    ];
    protected $guarded = [];
}