Refactor webpack into its own docker service.

Dockerfile

@@ -1,16 +1,8 @@
 FROM python:3.5
-RUN apt-get update
-RUN apt-get install -y nodejs npm
-RUN ln -s /usr/bin/nodejs /usr/bin/node
 RUN mkdir /code
 WORKDIR /code
 RUN mkdir requirements
 ADD ./bikeshop_project /code
 COPY ./requirements /code/requirements
 RUN pip install -r ./requirements/development.txt
-RUN npm install
-RUN npm install -g bower
-COPY ./bower.json .
-RUN bower install --allow-root
 EXPOSE 8000:8000
-EXPOSE 3000:3000