# you can avoid this line if you are in master...
git checkout master

# create a local gh-pages branch containing the splitted output folder
git subtree split --prefix dist -b gh-pages

# force the push of the gh-pages branch to the remote gh-pages branch at origin
git push -f origin gh-pages:gh-pages 

# delete the local gh-pages because you will need it: ref
git branch -D gh-pages