Dockerfile
FROM ruby:2.2
RUN gem install bundler
ADD Gemfile /app/Gemfile
ADD Gemfile.lock /app/Gemfile.lock
WORKDIR /app
RUN bundle install
ADD . /app
COPY ./config/database.yml.docker /app/config/database.yml
ADD https://github.com/ufoscout/docker-compose-wait/releases/download/2.3.0/wait /wait
ENV RAILS_ENV production
ENV RACK_ENV production
ENV DOCKER true
RUN bundle exec rake assets:precompile
CMD /wait && bundle exec rails server puma