controller.js

var Beer = require('./model')
  , Cervejaria = require('./model-cervejaria')
  ;

Cervejaria
.findOne()
.populate('beers')
.exec(function (err, cervejaria) {
  if (err) return console.log('Erro: ', err);
  console.log('Cervejaria', cervejaria);
  // prints "The creator is Aaron"
});

model-cervejaria.js

var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/workshop-be-mean-abril-2015');

var db = mongoose.connection;
db.on('error', function(err){
    console.log('Erro de conexao.', err)
});
db.on('open', function () {
  console.log('Conexão aberta.')
});
db.on('connected', function(err){
    console.log('Conectado')
});
db.on('disconnected', function(err){
    console.log('Desconectado')
});

var Schema = mongoose.Schema;

var _schema = { name: { type: String, default: '' }
  , created_at: { type: Date, default: Date.now }
  , beers: [{ type: Schema.Types.ObjectId, ref: 'Beer' }]
  }
  , Cervejariachema = new Schema(_schema);



module.exports = Cervejaria = mongoose.model('Cervejaria', Cervejariachema);


// var dados = {
//   name: 'SuissaBier'
// , beers: ['554188e6a43b404a3e0fc5f4']
// }
// var model = new Cervejaria(dados);

// model.save(function (err, data) {
//   if (err){
//     console.log('Erro: ', err);
//   }
//   else{
//     console.log('Cerveja Inserida: ', data);
//   }
// });

model.js

var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/workshop-be-mean-abril-2015');

var db = mongoose.connection;
db.on('error', function(err){
    console.log('Erro de conexao.', err)
});
db.on('open', function () {
  console.log('Conexão aberta.')
});
db.on('connected', function(err){
    console.log('Conectado')
});
db.on('disconnected', function(err){
    console.log('Desconectado')
});

var Schema = mongoose.Schema;

var _schema = { name: { type: String, default: '' }
  , description: { type: String, default: '' }
  , alcohol: { type: Number, min: 0, default: '' }
  , price: { type: Number, min: 0, default: '' }
  , category: { type: String, default: ''}
  , created_at: { type: Date, default: Date.now }
  }
  , BeerSchema = new Schema(_schema);

module.exports = mongoose.model('Beer', BeerSchema);