automate updating the borgbackup.github.io repo/website

cd docs ; make gh-io

docs/Makefile

@@ -138,5 +138,13 @@ gh-pages: html
 	(cd $$GH_PAGES_CLONE && git add -A && git commit -m 'Updated gh-pages' && git push) && \
 	rm -rf $$GH_PAGES_CLONE
 
+gh-io: html
+	GH_IO_CLONE="`mktemp -d`" && \
+    git clone git@github.com:borgbackup/borgbackup.github.io.git $$GH_IO_CLONE && \
+	(cd $$GH_IO_CLONE && git rm -r *) && \
+	cp -r _build/html/* $$GH_IO_CLONE && \
+	(cd $$GH_IO_CLONE && git add -A && git commit -m 'Updated borgbackup.github.io' && git push) && \
+	rm -rf $$GH_IO_CLONE
+
 inotify: html
 	while inotifywait -r . --exclude usage.rst --exclude '_build/*' ; do make html ; done