README-fetch-latest-changes-from-source.md

cd

cd local/cloned/fork-repo

Then, init the upstream, run

git remote add upstream git@github.com:TryGhost/Casper.git && \
git fetch upstream && \
git pull upstream master && \
git push;

Then, the next time you want to upgrade, run:

git fetch upstream && \
git pull upstream master && \
git push;