public function install($module_folder)
 {
     PC::install("Installing module.");
     $this->load->module($module_folder . "/setup");
     $this->module = new Module();
     $this->module->where('folder', $module_folder)->get();
     if (get_class($this->setup) != 'setup' || $this->module->installed == 'yes') {
         return $this->finish();
     }
     $this->module->folder = $module_folder;
     $this->module->save();
     $this->setup->module = null;
     $this->setup->module =& $this->module;
     if ($this->setup->install() !== false) {
         return $this->finish();
     }
 }