public void updateAuthority(HttpServletRequest request, HttpServletResponse response) 
            throws ServletException, IOException {
        
        String username = request.getParameter("username");
        String[] urls = request.getParameterValues("authority");
        
        List<Authority> authorities = dao.getAuthorities(urls);
        
        dao.update(username, authorities);
        
        response.sendRedirect(request.getContextPath() + "/authority/authority-manager.jsp");
        
    }

public void update(String username, List<Authority> authorities){
        users.get(username).setAuthorities(authorities);
    }