How to config Ajenti to run multiple module

I'm leaning Phalcon with multiple module. With struct.

• apps
  • frontend
    • controllers
    • models
    • views
    • Modules.php
  • backend
    • controllers
    • models
    • views
    • Modules.php
• public
  • css
  • js
  • img
  • index.php

And nginx config:

server {

listen *:80 default_server;
server_name localhost.dev;
access_log /var/log/nginx/localhostdev.access.log;
error_log /var/log/nginx/localhostdev.error.log;
root /srv/localhost.dev/public;
index index.html index.htm index.php;

   set $root_path '/srv/localhost.dev/public';

location / {
    root   $root_path;
    index  index.php index.html index.htm;

    # if file exists return it right away
    if (-f $request_filename) {
        break;
    }

    # otherwise rewrite it
    if (!-e $request_filename) {
        rewrite ^(.+)$ /index.php?_url=$1 last;
        break;
    }
}

location ~* ^/(css|img|js|flv|swf|download)/(.+)$ {
    root $root_path;
}

location ~ [^/]\.php(/|$) {
    fastcgi_index index.php;
    include fcgi.conf;
    fastcgi_pass unix:/var/run/ajenti-v-php-fcgi-localhostdev-php-fcgi-0.sock;
    fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
}

}

In public/index.php:

<?php 
$di->set('router', function ()
{
    $router = new Router();

    $router->setDefaultModule("frontend");

    $router->add('/:module/:controller/:action/:params', array(
        'module'     => 1,
        'controller' => 2,
        'action'     => 3,
        'params'     => 4
    ));
    return $router;
});
?>

When i access localhost.dev:

it print: Hello Frontend!

But, i access localhost.dev/frontend

it print: Frontend\Controllers\BackendController handler class cannot be loaded

How to fix it?

Additional question.

What I should config in nginx:

root /srv/localhost.dev;

location / { rewrite ^/$ /public/ break; rewrite ((?s).*) /public/$1 break; }

location /public/ { if (!-e $request_filename){ rewrite ^/((?s).*)$ /index.php?_url=/$1 break; } }

or

root /srv/localhost.dev/public;

if (-f $request_filename) { break; }

if (!-e $request_filename) { rewrite ^(.+)$ /index.php?_url=$1 last; break; }