Try Gitlab Page from CI

.gitlab-ci.yml

Gemfile

public/_config.yml

public/_includes/footer.html

public/_layouts/home.html

public/_layouts/page.html

public/annotations/README.md

public/collections/README.md

public/images/README.md

public/index.md

public/manifests/README.md

public/manifests/test3.json

public/manifests/test4.json

public/manifests/test5.json

public/plugins/annona/index.md

public/plugins/js/content-state.js

public/plugins/js/image.js

public/plugins/justified/jquery.justifiedGallery.min.js

public/plugins/justified/justifiedGallery.min.css

public/plugins/osd/index.md