Syncing theme at master with demo at gh-pages branch

After experimenting with Hugo for a while I would like to begin with a real repository. The theme itself should be hosted on he master. But I also want to integrate a demo of the theme on the gh-pages branch that contains a dummy site generated by Hugo.

So, what’s the best the to keep ./themes/<theme-name>/ on gh-pages in sync with the master branch?

Are you using a submodule for the the themes repo or do you have local copy of your theme?

If you are doing the latter I wouldn’t too much about keeping the branches in sync. The gh-pages branch holds completely different content from master in the majority of repos. The expectation usually is that you aren’t going to be merging the two because the content is so different.

The theme is currently a work in progress placed in a local copy. Submodules would require another repo, but that’s what I want to avoid.