http://codex.wordpress.org/Function_Reference/add_cap => kullanıcılara yetki ekler
http://codex.wordpress.org/Function_Reference/remove_cap =>yetki siler
add_action( 'admin_init', 'remove_editor_read_private_posts' );

function remove_editor_read_private_posts(){
global $wp_roles;
$wp_roles->remove_cap( 'editor', 'read_private_posts' );
}
http://codex.wordpress.org/Function_Reference/add_role => rol ekler