Je ne comprends pas l'intérêt de tout ce truc. Comme tu développes tes features dans une branche spécifique, tu as juste besoin de 

    git fetch upstream master // now we have the upstream/master branch locally
    git checkout master
    git merge upstream/master // now our local master branch is identical to the angularKS master branch
    git push origin/master  // now our github repo's master branch is identical to the angularJS master branch
    git checkout awesome-feature
    git rebase master // now our feature is a direct descendant of the lastest commit in angular master branch