added example auth server

Author: guumaster

example/auth_server.js

@@ -0,0 +1,44 @@
+var express = require('express');
+var bodyParser = require('body-parser');
+var FitbitClient = require('fitbit-client-oauth2');
+
+var app = express();
+
+var clientId = 'YOUR_CLIENT_ID';
+var clientSecret = 'YOUR_CLIENT_SECRET';
+
+var client = new FitbitClient(clientId, clientSecret);
+var redirect_uri = 'http://localhost:3000/auth/fitbit/callback';
+
+app.use(bodyParser());
+
+app.get('/auth/fitbit', function(req, res) {
+
+  var auth_url = client.getAuthorizationUrl('http://localhost:3000/auth/fitbit/callback');
+
+  res.redirect(auth_url);
+
+});
+
+app.get('/auth/fitbit/callback', function(req, res, next) {
+
+  client.getToken(req.query.code, redirect_uri)
+    .then(function(token) {
+
+      // ... save your token on session or db ...
+
+      // then redirect
+      //res.redirect(302, '/user');
+
+      res.send(token);
+
+    })
+    .catch(function(err) {
+      // something went wrong.
+      res.send(500, err);
+
+    });
+
+});
+
+app.listen(3000);