code: def register_app(app_name, app_setting, web_application_setting, mainfile, package_space):
      
      from turbo import log
      app_config.app_name = app_name
      app_config.app_setting = app_setting
      app_config.project_name = os.path.basename(get_base_dir(mainfile, 2))
      app_config.web_application_setting.update(web_application_setting)
      if app_setting.get('session_config'):
          app_config.session_config.update(app_setting['session_config'])
      log.getLogger(**app_setting.log)
      _install_app(package_space)
docs: insert current project root path into sys path