serve canvas as an endpoint

src/server/index.ts

@@ -102,6 +102,10 @@ app.get('/info', checkAuth, (req, res) => {
   res.json(req.user);
 });
 
+app.use('/canvas.png', (req, res) =>
+  res.sendFile(join(__dirname, '..', '..', 'canvas.png')),
+);
+
 app.use(express.static(join(__dirname, '..', 'public')));
 
 ///