add docs readme back

docs/README.md

@@ -0,0 +1,25 @@
+## Publish documentation for a new release.
+
+CircleCI job `pytorch_xla_linux_debian11_and_push_doc` is specified to run on `release/*` branches, but it was not
+run on release branches due to "Only build pull requests" setting. Turning off "Only build pull requests" will result
+in much larger volumes in jobs which is often unnecessary. We're waiting for [this feature request](https://ideas.circleci.com/ideas/CCI-I-215)
+to be implemented so that we could override this setting on some branches.
+
+Before the feature is available on CircleCi side, we'll use a manual process to publish documentation for release.
+[Documentation for master branch](http://pytorch.org/xla/master/) is still updated automatically by the CircleCI job.
+But we'll need to manually commit the new versioned doc and point http://pytorch.org/xla to the documentation of new
+stable release.
+
+Take 1.5 release as example:
+```
+# Build pytorch/pytorch:release/1.5 and pytorch/xla:release/1.5 respectively.
+# In pytorch/xla/docs
+./docs_build.sh
+git clone -b gh-pages https://github.com/pytorch/xla.git /tmp/xla
+cp -r build/* /tmp/xla/release/1.5
+cd /tmp/xla
+# Update `redirect_url` in index.md
+git add .
+git commit -m "Publish 1.5 documentation."
+git push origin gh-pages
+```