offer userns=keep-id podman based build option

README.template

@@ -43,6 +43,25 @@ and double-check the generated ``rendered/draft-*.html`` file before filing a Pu
 See `here <protocol/README.rst>`__ for the project dependencies.
 
 
+Building with Podman
+~~~~~~~~~~~~~~~~~~~~
+
+To build the rendered HTML without installing dependencies locally, use
+`Podman <https://podman.io/>`__ with the included ``Dockerfile``:
+
+.. code::
+
+   podman build -t zcash-zips-render .
+   podman run --rm --userns=keep-id -v "$(pwd):/zips" zcash-zips-render
+
+The ``--userns=keep-id`` flag ensures that rendered files are owned by your
+user rather than root. To render only the ZIPs (skipping protocol PDFs):
+
+.. code::
+
+   podman run --rm --userns=keep-id -v "$(pwd):/zips" zcash-zips-render all-zips
+
+
 Settled Mainnet Network Upgrade
 -------------------------------
 

render-via-docker.sh

@@ -3,5 +3,5 @@ set -efuxo pipefail
 
 TAG='zcash-zips-render'
 
-docker build -t "$TAG" .
-docker run -v "$(pwd):/zips" "$TAG"
+podman build -t "$TAG" .
+podman run --rm --userns=keep-id -v "$(pwd):/zips" "$TAG"