Add class to next and previous post_link

I recently needed to use this for a theme I was building figured I would post the results up here for everyone. Adding this snippet to the functions.php of your WordPress theme will add a custom class to next and previous post_link.

function add_class_next_post_link($html){
    $html = str_replace('<a','<a class="next"',$html);
    return $html;
}
add_filter('next_post_link','add_class_next_post_link',10,1);
function add_class_previous_post_link($html){
    $html = str_replace('<a','<a class="prev"',$html);
    return $html;
}
add_filter('previous_post_link','add_class_previous_post_link',10,1);