Multiplayer mode: server, room tokens, docker setup, and client UI

README.md

@@ -0,0 +1,53 @@
+# Tic Tac Toe
+
+A tic-tac-toe game with two modes: **CPU** (play against a minimax AI) and **Online** (real-time 2-player over WebSocket).
+
+## Stack
+- Frontend: vanilla JS + CSS (no build step)
+- Backend: Node.js + Express (serves static files) + `ws` (WebSocket) + `sql.js` (SQLite, in-memory)
+
+## Project layout
+```
+public/            frontend (index.html, app.js, game.js, multiplayer.js, style.css)
+server/            backend (server.js, db.js, package.json, pnpm-lock.yaml)
+docs/              design docs
+Dockerfile         production image
+docker-compose.yml
+```
+
+## Run locally
+
+The backend lives in `server/` (the frontend has no build step).
+
+```bash
+# install backend deps (pnpm)
+cd server && pnpm install
+
+# start (default port 8080)
+node server/server.js
+# or with an explicit port
+PORT=8080 node server/server.js
+```
+
+Then open <http://localhost:8080/>.
+
+> The server reads `PORT` (default `8080`) and optional `BASE_PATH` (default empty).
+
+## Run with Docker
+
+```bash
+docker compose up --build
+```
+
+or build and run the image directly:
+
+```bash
+docker build -t tictactoe .
+docker run -p 8080:8080 tictactoe
+```
+
+Then open <http://localhost:8080/>.
+
+## Notes
+- `server/data/` holds the SQLite file and is git-ignored.
+- Online games persist to SQLite; a host who reloads can re-enter via the saved token.