add gulp stuff to build process

Dockerfile

@@ -6,7 +6,12 @@ WORKDIR /usr/src/app
 
 COPY package.json /usr/src/app/
 RUN npm install
+RUN npm install gulp-rev-replace gulp-clean gulp-fingerprint gulp-rev gulp-rev-all gulp-rev-replace
+RUN npm install -g --save-dev gulp
+
 COPY . /usr/src/app
+RUN gulp styles
+
 RUN npm cache clean
 
 CMD [ "npm", "start" ]