wordpress add custom role and capability

add_role_capability.php

// add custom role & capability
add_action('admin_init', 'add_custom_role');
function add_custom_role()
{

    $marketing = add_role('marketing',
                           'Marketing',
                           array(
                               'read' => true,
                               'manage_links',
                               'manage_categories',
                               'moderate_comments',
                               'view-stats')
    );

    if (null !== $marketing) {
        $role = get_role('administrator');
        $role->add_cap('view-stats');
    }

    // remove capability
    $role = get_role( 'contributor' );
    $role->remove_cap( 'read' );

    $myRole = add_role('myRole',
        'My Role',
        array(
            'read' => true
//            ,'view-stats'
        )
    );


}