code: function locateRootFolder() {
      var firstDefaultPlugin = DEFAULT_PLUGINS.first();
      var pluginPath = resolve.sync(firstDefaultPlugin.getNpmID() + '/package.json', {
          basedir: __dirname
      });
      var nodeModules = path.resolve(pluginPath, '../../..');
  
      return nodeModules;
  }
docs: Resolve the root folder containing for node_modules
  since gitbook can be used as a library and dependency can be flattened.
  
  @return {String} folderPath