git submodule add git://github.com/cedriclombardot/AdmingeneratorGeneratorBundle.git vendor/bundles/Admingenerator/ActiveAdminThemeBundle

<?php
// app/AppKernel.php

public function registerBundles()
{
    $bundles = array(
        // ...

        // Admin Generator
        new Admingenerator\GeneratorBundle\AdmingeneratorGeneratorBundle(),
        new Admingenerator\ActiveAdminThemeBundle\AdmingeneratorActiveAdminThemeBundle(),
    );

    // ...
}

admingenerator_generator:
    base_admin_template: AdmingeneratorActiveAdminThemeBundle::base_admin.html.twig

admingenerator_generator:
    base_admin_template: AdmingeneratorActiveAdminThemeBundle::base_admin_assetic_less.html.twig

    php app/console assets:install web/