docs: Add instructions for Google App Engine deployment

README.md

@@ -234,6 +234,67 @@ This will start a peerjs server on port 9000 exposed on port 9000 with key `peer
 
 Open your browser with http://localhost:9000/myapp It should returns JSON with name, description and website fields. http://localhost:9000/myapp/peerjs/id - should returns a random string (random client id)
 
+## Running in Google App Engine
+
+Google App Engine will create an HTTPS certificate for you automatically,
+making this by far the easiest way to deploy PeerJS in the Google Cloud
+Platform.
+
+1. Create a `package.json` file for GAE to read:
+
+```sh
+echo "{}" > package.json
+npm install express@latest peer@latest
+```
+
+2. Create an `app.yaml` file to configure the GAE application.
+
+```yaml
+runtime: nodejs
+
+# Flex environment required for WebSocket support, which is required for PeerJS.
+env: flex
+
+# Limit resources to one instance, one CPU, very little memory or disk.
+manual_scaling:
+  instances: 1
+resources:
+  cpu: 1
+  memory_gb: 0.5
+  disk_size_gb: 0.5
+```
+
+3. Create `server.js` (which node will run by default for the `start` script):
+
+```js
+const express = require('express');
+const { ExpressPeerServer } = require('peer');
+const app = express();
+
+app.enable('trust proxy');
+
+const PORT = process.env.PORT || 9000;
+const server = app.listen(PORT, () => {
+  console.log(`App listening on port ${PORT}`);
+  console.log('Press Ctrl+C to quit.');
+});
+
+const peerServer = ExpressPeerServer(server, {
+  path: '/'
+});
+
+app.use('/', peerServer);
+
+module.exports = app;
+```
+
+4. Deploy to an existing GAE project (assuming you are already logged in via
+`gcloud`), replacing `YOUR-PROJECT-ID-HERE` with your particular project ID:
+
+```sh
+gcloud app deploy --project=YOUR-PROJECT-ID-HERE --promote --quiet app.yaml
+```
+
 ## Privacy
 
 See [PRIVACY.md](https://github.com/peers/peerjs-server/blob/master/PRIVACY.md)