public function includeRole( core_kernel_classes_Resource $role,  core_kernel_classes_Resource $roleToInclude)
    {
        $includesRoleProperty = new core_kernel_classes_Property(GenerisRdf::PROPERTY_ROLE_INCLUDESROLE);
        
        // Clean to avoid double entries...
        $role->removePropertyValues($includesRoleProperty, array('like' => false, 'pattern' => $roleToInclude->getUri()));
        
        // Include the Role.
        $role->setPropertyValue($includesRoleProperty, $roleToInclude->getUri());
        
        // Reset cache.
        core_kernel_users_Cache::removeIncludedRoles($role);
    }