microservice-orders-api/app/Order.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Order extends Model
{

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [
        'quantity',
        'discount',
        'total_price',
        'product_id'
    ];

}