code: function _getFiles (route) {
    const dir = route[0]
    const prefix = route.splice(1).join('/')
  
    return _browseDir(dir)
      .map(file => require(file))
      .reduce((acc, routes) => acc.concat(routes), [])
      .map(routes => _normalizeUrl(routes, prefix))
  }
docs: return all imported routes
  @param  {Array.<String...>} route   directory with extra configuration
  @return {Array.<Object>}            imported routes