Add link to Gulp

docs/composer/plugin/drupal-dev-environment/index.md

@@ -43,5 +43,5 @@ The development plugin provides tools, that are common for working with themes i
 - [Gulp.js](https://gulpjs.com/)
 
 Now you can create or use existing `package.json` or `gulp.js` files for building your `css`, e.g.
-using [Sass](https://sass-lang.com/).
+using [Sass](https://sass-lang.com/). See more information [here](../../../docker/node/gulp-sass.md).