Retrieve instead of define user model in facebook oauth configuration

Author: omriAckley

generated/server/app/configure/authentication/facebook.js

@@ -4,7 +4,7 @@ var FacebookStrategy = require('passport-facebook').Strategy;
 
 module.exports = function (app, db) {
 
-    var User = db.define('user');
+    var User = db.model('user');
 
     var facebookConfig = app.getValue('env').FACEBOOK;