itskp-odense/Backend/controller/update.php

<?php

require "../../bootstrap.php";

use Backend\Model\Post;

if(isset($_POST['update'])){
    $post = Post::query()->find($_POST['id']);
    $post->title = $_POST['upTitle'];
    $post->description = $_POST['upDescription'];

    if(!$post->update()){
        echo "Error could not update";
    }else{
        header("location: ../../Frontend/admin.php");
    }
}