Synchronize with upstream

.gitconfig

...
[alias]
        synchronize-with-upstream = !~/synchronize-with-upstream.sh
...

synchronize-with-upstream.sh

#!/bin/sh

die () {
    echo >&2 "$@"
    exit 1
}

[ "$#" -eq 1 ] || die "Branch should be provided as argument."

git checkout $1
git fetch upstream
git reset --hard upstream/$1 
git push origin -f $1