Certified/app/Models/Concerns/OwnedByUser.php

<?php

namespace App\Models\Concerns;

use App\Models\User;
use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Support\Facades\Auth;

trait OwnedByUser
{
    protected static function bootOwnedByUser(): void
    {
        static::creating(function (self $model) {
            if (! isset($model->user_id) && ($user = Auth::user()) !== null) {
                $model->user_id = $user->id;
            }
        });
    }

    /**
     * @return BelongsTo<User, $this>
     */
    public function user(): BelongsTo
    {
        return $this->belongsTo(User::class);
    }
}