updates frapi core while preserving a symlink to a self-managed custom/ folder

update_frapi_core.sh

#!/bin/bash

#assumes working copy is a fork & upstream is set to git@github.com:frapi/frapi.git

# temporarily move custom symlink
mv src/frapi/custom src/frapi/custom_symlink && 

# reset any changes (i.e. deletion of custom folder)
git reset --hard && 

# fetch the upstream HEAD
git fetch upstream && 

# merge in upstream
git merge upstream/master &&

# move the custom/ folder
mv src/frapi/custom src/frapi/custom_bak

# restore the original symlink
mv src/frapi/custom_symlink src/frapi/custom