public function action_index()
{
$data = array();
if (!is_readable(APPPATH . 'config/database.php')) {
Request::initial()->redirect('install');
}
$cat = new Model_Category();
$materials = new Model_Material();
$cat->checkTree();
$tree = $cat->getTree();
$data['tree'] = $cat->getITree($tree);
$data['teachers'] = $materials->getTeachersGropupByNode();
$this->tpl->content = View::factory('main', $data);
}
