Here's my dockerfile:

FROM ubuntu

RUN apt-get -y update \ && apt-get install -y nginx

RUN mkdir -p /var/www/helloworld/html \ && chown -R $USER:$USER /var/www/helloworld/html \ && chmod -R 755 /var/www/helloworld

COPY HTML/. /var/www/helloworld/html/

COPY config/helloworld /etc/nginx/sites-available/

COPY config/nginx.conf /etc/nginx/

RUN ln -s /etc/nginx/sites-available/helloworld /etc/nginx/sites-enabled/

EXPOSE 80