Experiment with cache mount

production.Dockerfile

@@ -64,9 +64,14 @@ RUN ./bin/rails assets:precompile
 FROM base
 
 # Install packages needed for deployment
-RUN apt-get update -qq && apt-get install -yq --no-install-recommends \
-  libpq-dev \
-  && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+RUN --mount=type=cache,target=/var/cache/apt \
+  --mount=type=cache,target=/var/lib/apt,sharing=locked \
+  --mount=type=tmpfs,target=/var/log \
+  rm -f /etc/apt/apt.conf.d/docker-clean; \
+  echo 'Binary::apt::APT::Keep-Downloaded-Packages "true";' > /etc/apt/apt.conf.d/keep-cache; \
+  apt-get update -qq \
+  && apt-get install -yq --no-install-recommends \
+  libpq-dev
 
 # Copy built artifacts: gems, application
 COPY --from=build /usr/local/bundle /usr/local/bundle