chore: add update instruction to README

README.md

@@ -377,6 +377,45 @@ Enable SSL on nginx (Accept all information asked):
 sudo certbot --nginx
 ```
 
+## Upgrading
+
+WhaTicket is a working in progress and we are adding new features frequently. To update your old installation and get all the new features, you can use a bash script like this:
+
+**Note**: Always check the .env.example and adjust your .env file before upgrading, since some new variable may be added.
+
+```bash
+nano updateWhaticket
+```
+
+```bash
+#!/bin/bash
+echo "Updating Whaticket, please wait."
+
+cd ~
+cd whaticket
+git pull
+cd backend
+npm install
+rm -rf dist
+npm run build
+npx sequelize db:migrate
+npx sequelize db:seed
+cd ../frontend
+npm install
+rm -rf build
+npm run build
+pm2 restart all
+
+echo "Update finished. Enjoy!"
+```
+
+Make it executable and run it:
+
+```bash
+chmod +x updateWhaticket
+./updateWhaticket
+```
+
 ## Contributing
 
 Any help and suggestions are welcome!