diff --git a/README.md b/README.md
index 9640415bfe13d82ac04a529e0fbca0d309d5715b..60ae19a5b45f2680255e638597a38c405571190b 100644
--- a/README.md
+++ b/README.md
@@ -33,7 +33,7 @@ COPY config.json /config.json
 # Render the website. Create an archive for offline usage.
 RUN render-runbooks --config=/config.json
 RUN cp -r /src/static/* /src/public/
-RUN tar -C /src/public -x -z -v -f /runbooks.tgz .
+RUN tar -C /src/public -c -z -v -f /runbooks.tgz .
 
 # Use the static-content simple static HTTP server image, and copy
 # the rendered runbooks from the build stage.