feat: update functions README

Author: exaby73

functions/README.md

@@ -26,7 +26,20 @@ Getting Started
       - You should be getting the result of the addition.
  11. Write a message in the Box below and Click the "Add Message" button.
       - The message is added below but if it contains [bad words](https://github.com/web-mech/badwords-list) or SHOUTING!! it will be sanitized.
-
+ 
+To run the sample app locally during development:
+1. Run `npm install` to install dependencies.
+2. Run `npm --prefix functions run build` to build the functions using Vite.
+3. Run `firebase emulators:start` to start the local Firebase emulators.
+4. Run `npm run dev` to serve the app locally using Vite
+   This will start a server locally that serves `index.html` on `http://localhost:5173/index.html`.
+
+Running the app using the Firebase CLI:
+1. Run `npm install` to install dependencies.
+2. Run `npm run build` to build the app using Vite.
+3. Run `firebase emulators:start` to start the local Firebase emulators.
+4. In your terminal output, you will see the "Hosting" URL. By default, it will be `127.0.0.1:5002`, though it may be different for you.
+5. Navigate in your browser to the URL output by the `firebase emulators:start` command.
 
 Support
 -------