Added authentication routes for express.

backend/routes/authRoutes.js

@@ -0,0 +1,11 @@
+const express = require('express');
+const passport = require('passport');
+require('../config/passport-setup');
+
+const router = express.Router();
+
+router.post('/login', passport.authenticate('local'), (req, res) => {
+  res.send(req.user);
+});
+
+module.exports = router;