profile.php

<?php

hm_rewrite_rule( array(

    'regex'     => '^users/([^/]+)/?',
    'query'     => 'author_name=$matches[1]&',
    'template'  => 'user-archive.php',
    'body_class_callback' => function( $classes ) {
        $classes[] = 'user-archive';
        $classes[] = 'user-' . get_query_var( 'author_name' );
        return $classes;
    },
    'title_callback' => function( $title, $seperator ) {
        return get_query_var( 'author_name' ) . ' ' . $seperator . ' ' . $title;
    }
) );