code: def show():
      
      if not is_configured():
          raise JutException('No configurations available, please run: `jut config add`')
  
      info('Available jut configurations:')
      index = 0
      for configuration in _CONFIG.sections():
          username = _CONFIG.get(configuration, 'username')
          app_url = _CONFIG.get(configuration, 'app_url')
  
          if app_url != defaults.APP_URL:
              if _CONFIG.has_option(configuration, 'default'):
                  info(' %d: %s@%s (default)', index + 1, username, app_url)
              else:
                  info(' %d: %s@%s', index + 1, username, app_url)
  
          else:
              if _CONFIG.has_option(configuration, 'default'):
                  info(' %d: %s (default)' % (index + 1, username))
              else:
                  info(' %d: %s' % (index + 1, username))
  
          index += 1
docs: print the available configurations directly to stdout