laravel-beginning/form-app-with-data/app/Models/Category.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;

class Category extends Model
{
    use HasFactory;
    protected $fillable = ['name'];
    
    public function contactMessages() { return $this->hasMany(ContactMessage::class); }
}