public IHttpActionResult UpdateRole(Guid roleId, UpdateRoleCommand command)
        {
            if (roleId == Guid.Empty)
            {
                throw new ArgumentException("roleId must be defined.");
            }
            if (command == null)
            {
                throw new ArgumentNullException("command");
            }
            if (string.IsNullOrWhiteSpace(command.Name))
            {
                throw new ArgumentException("Role name must be defined.");
            }

            identityManagementService.UpdateRole(roleId, command.Name, command.Description, command.ExternalGroupName);

            return Ok();
        }