chore(webui): better build command

- clean before build (mode force)
- update documentation
- update `Makefile`
- ordering build

webui/Dockerfile

@@ -10,6 +10,7 @@ COPY .bowerrc $WEBUI_DIR/
 COPY bower.json $WEBUI_DIR/
 
 WORKDIR $WEBUI_DIR
+RUN npm set progress=false
 RUN npm install
 RUN bower install --allow-root
 

webui/gulp/build.js

@@ -92,7 +92,7 @@ gulp.task('other', function () {
 });
 
 gulp.task('clean', function () {
-  return $.del([path.join(conf.paths.dist, '/'), path.join(conf.paths.tmp, '/')]);
+  return $.del([path.join(conf.paths.dist, '/**'), '!' + conf.paths.dist, path.join(conf.paths.tmp, '/')], {force: true});
 });
 
 gulp.task('build', ['html', 'fonts', 'other']);

webui/readme.md

@@ -28,7 +28,7 @@ make generate-webui  # Generate static contents in `traefik/static/` folder.
   - `bower install`
 
 - Build static Web UI, execute the following command:
-  - `gulp build`
+  - `gulp`
 
 - Static contents are build in the directory `static`