I am using Loopback and want to persist data to the database through a script. 

I have written a custom command which I will be running through a cronjob: 

```
'use strict';

var loopback = require('loopback');
var app = module.exports = loopback();
var boot = require('loopback-boot');

app.start = function() {
  return app.listen(function() {
    const baseUrl = app.get('url').replace(/\/$/, '');
    console.log('Web server listening at: %s', baseUrl);
    let Dish = app.models.dish;
    console.log(Dish);
  })
}

boot(app, __dirname, function(err) {
  if (err) throw err;

  // start the server if `$ node server.js`
  if (require.main === module)
    app.start();
});

```

The output I get is:

```
Web server listening at: http://localhost:3000
undefined

```

How do I access the dish model?