Issue convert jade to handlebars

I am trying to rewrite some code that was written in jade. I need to use express-handlebars or something else that does not alter the entire structure of html file. My question is: how to pass parameters in the new version, for example, the following one which is user?

The old working version using jade:

app.js

var router = require('express').Router();
router.get('/', function(req, res) {
  res.render('index', {user: req.user});
});

index.jade

block content
  if (user)
    p You are currently logged in as #{user.username}
  else
    p You are currently not logged in. Please login or register...

The new version using handlebars:

index.handlebars

<div class="content"></div>

So what should I write in the new index.handlebars file and/or what to change in app.js in order to display the user.username correctly? I am quite new to this so I appreciate anything that helps.

via tic30