add update.sh example script

#!/bin/sh

#

# Updates a travelynx instance deployed via git. Performs database migrations

# as necessary.

git pull

if [ "$1" = "with-deps" ]; then

	mkdir local.new

	cd local.new

	cp ../cpanfile* .

	carton install

	cd ..

	sudo systemctl stop travelynx

	mv local local.old

	mv local.new/local .

	perl index.pl database migrate

	sudo systemctl start travelynx

elif perl index.pl database has-current-schema; then

	sudo systemctl reload travelynx

else

	sudo systemctl stop travelynx

	perl index.pl database migrate

	sudo systemctl start travelynx

fi