Add Workflow for building and releasing Docker image

Dockerfile

@@ -0,0 +1,77 @@
+# Make sure RUBY_VERSION matches the Ruby version in .ruby-version and Gemfile
+ARG RUBY_VERSION=3.2.2
+FROM registry.docker.com/library/ruby:$RUBY_VERSION-slim as base
+
+# Rails app lives here
+WORKDIR /rails
+
+# Set production environment
+ENV RAILS_ENV="production" \
+    BUNDLE_DEPLOYMENT="1" \
+    BUNDLE_PATH="/usr/local/bundle" \
+    BUNDLE_WITHOUT="development"
+
+
+# Throw-away build stage to reduce size of final image
+FROM base as build
+
+# Install packages needed to build gems and node modules
+RUN apt-get update -qq && \
+    apt-get install --no-install-recommends -y build-essential git libvips pkg-config curl node-gyp default-libmysqlclient-dev
+
+# Install JavaScript dependencies
+ARG NODE_VERSION=20.5.0
+ARG YARN_VERSION=1.22.19
+ENV PATH=/usr/local/node/bin:$PATH
+RUN curl -sL https://github.com/nodenv/node-build/archive/master.tar.gz | tar xz -C /tmp/ && \
+    /tmp/node-build-master/bin/node-build "${NODE_VERSION}" /usr/local/node && \
+    npm install -g yarn@$YARN_VERSION && \
+    rm -rf /tmp/node-build-master
+
+
+# Install application gems
+COPY Gemfile Gemfile.lock ./
+RUN bundle install && \
+    rm -rf ~/.bundle/ "${BUNDLE_PATH}"/ruby/*/cache "${BUNDLE_PATH}"/ruby/*/bundler/gems/*/.git && \
+    bundle exec bootsnap precompile --gemfile
+
+# Install node modules
+#COPY package.json yarn.lock ./
+#RUN yarn install --frozen-lockfile
+
+# Copy application code
+COPY . .
+
+# Precompile bootsnap code for faster boot times
+RUN bundle exec bootsnap precompile app/ lib/
+
+# Precompiling assets for production without requiring secret RAILS_MASTER_KEY
+RUN SECRET_KEY_BASE_DUMMY=1 ./bin/rails assets:precompile
+
+
+# Final stage for app image
+FROM base
+LABEL org.opencontainers.image.source=https://github.com/projekteuler/projekteuler
+LABEL org.opencontainers.image.description="Projekteuler production image"
+LABEL org.opencontainers.image.licenses=MIT
+
+# Install packages needed for deployment
+RUN apt-get update -qq && \
+    apt-get install --no-install-recommends -y curl node-gyp default-mysql-client libvips && \
+    rm -rf /var/lib/apt/lists /var/cache/apt/archives
+
+# Copy built artifacts: gems, application
+COPY --from=build /usr/local/bundle /usr/local/bundle
+COPY --from=build /rails /rails
+
+# Run and own only the runtime files as a non-root user for security
+RUN useradd rails --create-home --shell /bin/bash && \
+    chown -R rails:rails db log tmp
+USER rails:rails
+
+# Entrypoint prepares the database.
+ENTRYPOINT ["/rails/bin/docker-entrypoint"]
+
+# Start the server by default, this can be overwritten at runtime
+EXPOSE 3000
+CMD ["./bin/rails", "server"]