refactor(app.js, auth.js): Extract all auth method to individual modules

lib/web/auth/twitter/index.js

@@ -0,0 +1,29 @@
+'use strict'
+
+const Router = require('express').Router
+const passport = require('passport')
+const TwitterStrategy = require('passport-twitter').Strategy
+
+const config = require('../../../config')
+const {setReturnToFromReferer, passportGeneralCallback} = require('../utils')
+
+let twitterAuth = module.exports = Router()
+
+passport.use(new TwitterStrategy({
+  consumerKey: config.twitter.consumerKey,
+  consumerSecret: config.twitter.consumerSecret,
+  callbackURL: config.serverurl + '/auth/twitter/callback'
+}, passportGeneralCallback))
+
+twitterAuth.get('/auth/twitter', function (req, res, next) {
+  setReturnToFromReferer(req)
+  passport.authenticate('twitter')(req, res, next)
+})
+
+// twitter auth callback
+twitterAuth.get('/auth/twitter/callback',
+  passport.authenticate('twitter', {
+    successReturnToOrRedirect: config.serverurl + '/',
+    failureRedirect: config.serverurl + '/'
+  })
+)