WordPress - Add Registration Date as a sortable column for users

class-user-registration-column.php

<?php
/**
 * Add Registration Date as a sortable column for users
 */
class NH_User_Registration_Column {

    function __construct() {
        add_filter( 'manage_users_columns',          array($this, 'manage_users_columns') );
        add_filter( 'manage_users_custom_column',    array($this, 'manage_users_custom_column'), 10, 3 );
        add_filter( 'manage_users_sortable_columns', array($this, 'manage_users_sortable_columns') );
    }

    /*
     * Create a column
     * @param array $columns Array of all user table columns {column ID} => {column Name}
     */
    public function manage_users_columns($columns) {
        $new_columns = array();
        foreach($columns as $key => $name):
            if($key == 'posts') $new_columns['registration_date'] = 'Registration date';
            // Add new column before posts column for better formatting
            $new_columns[$key] = $name;
        endforeach;
        return $new_columns;
    }

    /*
     * Fill our new column with the registration dates of the users
     * @param string $row_output text/HTML output of a table cell
     * @param string $column_id  column ID
     * @param int    $user       user ID (in fact - table row ID)
     */
    public function manage_users_custom_column($row_output, $column_id, $user) {
        $date_format = 'M j, Y';

        switch ( $column_id ) {
            case 'registration_date' :
                return date( $date_format, strtotime( get_the_author_meta( 'registered', $user ) ) );
                break;
            default:
        }

        return $row_output;
    }

    /*
     * Make our "Registration date" column sortable
     * @param array $columns Array of all user sortable columns {column ID} => {orderby GET-param}
     */
    public function manage_users_sortable_columns($columns) {
        return wp_parse_args( array( 'registration_date' => 'registered' ), $columns );

    }
}
new NH_User_Registration_Column;