python -m SimpleHTTPServer 8005
git checkout master
you can avoid this line if you are in master...
git subtree split --prefix app -b gh-pages
create a local gh-pages branch containing the splitted output folder
git push -f origin gh-pages:gh-pages
force the push of the gh-pages branch to the remote gh-pages branch at origin
git branch -D gh-pages
delete the local gh-pages because you will need it: ref
git checkout gh-pages
go to the gh-pages branch
git rebase master
bring gh-pages up to date with master
git push origin gh-pages
commit the changes
git checkout master
return to the master branch