code: function importerExpress(expressApp, options) {
      var importTo = '/';
      if (typeof options === 'object') {
          importTo = options.routePath || importTo;
      }
  
      importerSync(options, function (router, name) {
          if (name === 'index') expressApp.use(importTo, router);
          expressApp.use(path.join(importTo, name), router);
      });
  }
docs: This handler is called when Importer imports each module object.
  @callback eachModule
  @param module Module object. (module.exports in module source)
  @param name Module name. extension is excluded. (ex: foo.js -> "foo")
   
  Use all modules in a directory as a express route.
  NOTE: you need to export express.Router object in module.
  
  @param expressApp Express App Instance
  @param options Import options. (or module directory path)
  - path : The module directory path. (You can use relavant path)
  - routePath : The path to connect route (default is '/')