Simple production Dockerfile

Dockerfile

FROM ruby:2.3-alpine

ADD Gemfile* /app/

RUN apk add --no-cache --virtual .build-deps build-base \
    && apk add --no-cache postgresql-dev tzdata \
    && cd /app; bundle install --without test production \
    && apk del .build-deps

ADD . /app
RUN chown -R nobody:nogroup /app
USER nobody

ENV RAILS_ENV production

WORKDIR /app
CMD ["bundle", "exec", "rails", "s", "-b", "0.0.0.0", "-p", "8080"]