A Dockerfile for a Rails app

Dockerfile

FROM ruby:2.3

# Set the base directory used in any further RUN, COPY, and ENTRYPOINT
# commands.
RUN mkdir -p /app
WORKDIR /app

# Copy dependencies into the container
COPY Gemfile Gemfile.lock ./ 
RUN gem install bundler && bundle install --jobs 20 --retry 5 --without development test

# Set the Rails environment to production
ENV RAILS_ENV production 
ENV RACK_ENV production

# Copy the main application into the container
COPY . ./

# Precompile the Rails assets
RUN bundle exec rake assets:precompile

# Start the application with Puma
CMD bundle exec puma -C config/puma.rb