Add dev setup to readme

README.md

@@ -0,0 +1,12 @@
+The project is based on [Kirby CMS](https://getkirby.com), [Vite](https://vitejs.dev/) + [Vue](https://fr.vuejs.org/) and [Pinia](https://pinia.vuejs.org/) as a state manager.
+Vue is used following the composition API approach.
+
+## First setup :
+
+- **From the `/public` directory**, install the Kirby dependencies : `composer install`
+- **From the root directory**, install the Node dependencies : `npm install`
+
+## Development environment
+
+- **From the `/public` directory**, launch the PHP server : `php -S localhost:8888 kirby/router.php`
+- In another terminal tab, **from the root directory**, launch the Vite server : `vite`