Set all site users as active

/**
 * A drop-in code snippet to set all users on the site as 
 * "activated" (when using the plugin's moderated registration
 * setting). All existing users on the site will be set as 
 * active without affecting passwords and no email will be sent.
 *
 * To Use:
 * 1. Save the code snippet to your theme's functions.php
 * 2. Go to Tools > Activate All Users.
 * 3. Follow prompts on screen.
 * 4. Remove the code snippet when completed.
 */
add_action( 'init', 'activate_all_users_init' );
function activate_all_users_init() {
    global $wpmem;
    $wpmem->activate_all_users = New My_Activate_All_Users_Class();
}
class My_Activate_All_Users_Class {
 
    function __construct() {
        add_action( 'admin_menu', array( $this, 'admin_menu' ) );
    }

    function admin_menu() {
        $hook = add_management_page( 'Activate All Users Page', 'Activate All Users', 'edit_users', 'activate-all-users', array( $this, 'admin_page' ), '' );
        add_action( "load-$hook", array( $this, 'admin_page_load' ) );
    }

    function admin_page_load() {
        global $activate_all_complete;
        $activate_all_complete = false;
        if ( isset( $_GET['page'] ) && 'activate-all-users' == $_GET['page'] && isset( $_POST['activate-all-confirm'] ) && 1 == $_POST['activate-all-confirm'] ) {
            $users = get_users( array( 'fields'=>'ID' ) );
            foreach ( $users as $user_id ) {
                update_user_meta( $user_id, 'active', 1 );
                wpmem_set_user_status( $user_id, 0 );
            }
            $activate_all_complete = true;
        }
    }

    function admin_page() {
        global $activate_all_complete;
        echo "<h2>Activate All Users</h2>";
        if ( $activate_all_complete ) {
            echo '<p>All users were activated.<br />';
            echo 'You may now remove this code snippet if desired.</p>';
        } else {
            $form_post = ( function_exists( 'wpmem_admin_form_post_url' ) ) ? wpmem_admin_form_post_url() : '';
            echo "<p>This process will mark all existing user accounts as activated in WP-Members.<br />It will not change any passwords or send any emails to users.";
            echo '<form name="activate-all-users" id="activate-all-users" method="post" action="' . $form_post . '">';
            echo '<p><input type="checkbox" name="activate-all-confirm" value="1" /><label for="activate-all-confirm">Activate all users?</label></p>';
            echo '<p><input type="submit" name="submit" value="Submit" /></p>';
            echo '</form>';
        }
    }
}
// End of My_Activate_All_Users_Class