related short code

function widget_shortcode() {

    global $post;

$current_post_type = get_post_type( $post );

// The query arguments
$args = array(
    'posts_per_page' => 3,
    'order' => 'DESC',
    'orderby' => 'ID',
    'post_type' => $current_post_type,
    'post__not_in' => array( $post->ID )
);

// Create the related query
$rel_query = new WP_Query( $args );

// Check if there is any related posts
if( $rel_query->have_posts() ) :
ob_start();
?>
<h4 class="widget-title toprelated">אולי יעניין אותך גם</h4>
   <div id="related" class="group">
    <ul class="group">
<?php
    // The Loop
    while ( $rel_query->have_posts() ) :
        $rel_query->the_post();
?>
        <li>
        <a href="<?php the_permalink() ?>" title="<?php the_title() ?>" rel="bookmark">
            <article>
                 <div class="thethumbnail"><?php the_post_thumbnail( array(300, 250) ); ?></div>
                <h4 class="entry-title"><?php the_title() ?></h4>

            </article>
        </a>
        </li>
<?php
    endwhile;
?>
    </ul><!-- .group -->
</div><!-- #related -->
<?php
return ob_get_clean();
endif;

// Reset the query
wp_reset_query();


 }
add_shortcode( 'related', 'widget_shortcode' );

//run shortcode in text widget

add_filter('widget_text','do_shortcode');