[Dynamic slug in Laravel 7] Step2: Fill out the value of UUID in Post.php

<?php

namespace App\Models;

class Post extends Model implements HasMedia, ShouldHaveTypes
{
    // ...
    
    // Add/override the boot function
    protected static function boot()
    {
        parent::boot();

        static::creating(function ($query) {
            $query->uuid = \App\Http\Controllers\Controller::uuid();
        });
    }
    // ...
}