add update.sh example script

update.sh

+#!/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