update README.md

Author: LinaBell

README.md

@@ -2,6 +2,20 @@
 
 Race App is an exciting racing game built with Node.js and React. Players compete to complete a virtual race course in the fastest time possible by navigating through a series of waypoints. The app features a leaderboard that displays the top 20 fastest race times, allowing players to compare their performance with others.
 
+## Built With
+
+### Client
+
+![React](https://img.shields.io/badge/react-%2320232a.svg?style=for-the-badge&logo=react&logoColor=%2361DAFB)
+![Vite](https://img.shields.io/badge/vite-%23646CFF.svg?style=for-the-badge&logo=vite&logoColor=white)
+![TypeScript](https://img.shields.io/badge/typescript-%23007ACC.svg?style=for-the-badge&logo=typescript&logoColor=white)
+![Tailwind CSS](https://img.shields.io/badge/tailwindcss-%2338B2AC.svg?style=for-the-badge&logo=tailwind-css&logoColor=white)
+
+### Server
+
+![Node.js](https://img.shields.io/badge/node.js-%2343853D.svg?style=for-the-badge&logo=node.js&logoColor=white)
+![Express](https://img.shields.io/badge/express-%23000000.svg?style=for-the-badge&logo=express&logoColor=white)
+
 ## Features
 
 - Interactive race course with a visual racetrack loop and multiple waypoints
@@ -53,3 +67,33 @@ To reset the race stats to a default unplayed state:
 
 Click the "Admin" button in the drawer.
 On the admin page, click the "Reset Race Stats" button to remove all previously attained race times.
+
+## Implementation Requirements
+
+### Required Assets with Unique Names
+
+The following assets must exist in the world with specific unique names:
+
+| Unique Name | Description |
+|-------------|-------------|
+| `race-track-container` | A rectangle asset that surrounds the entire race track area. Used to determine placement position when switching tracks. |
+| `race-track-checkpoint` | Checkpoint assets placed along the track. Multiple checkpoints should use partial matching (e.g., `race-track-checkpoint-1`, `race-track-checkpoint-2`). |
+| `race-track-start` | The starting line asset where players begin the race. |
+
+### Additional Environment Variables
+
+In addition to the standard environment variables, this app supports Google Sheets integration for leaderboards:
+
+| Variable | Description |
+|----------|-------------|
+| `GOOGLESHEETS_CLIENT_EMAIL` | Google service account email for Sheets API access |
+| `GOOGLESHEETS_SHEET_ID` | The ID of the Google Spreadsheet for storing leaderboard data |
+| `GOOGLESHEETS_PRIVATE_KEY` | Service account private key for authentication |
+
+### Track Configuration
+
+Tracks are configured in `server/constants.js`. Each track requires:
+- `id`: Unique track identifier
+- `name`: Display name for the track
+- `thumbnail`: URL to track preview image
+- `sceneId`: The Topia scene ID containing the track assets