Example of implementing a hasMany / belongsTo relationship in EmberFire

app.js

var App = Ember.Application.create({});

var Promise = Ember.RSVP.Promise;

// ADAPTER

App.ApplicationAdapter = DS.FirebaseAdapter.extend({
  firebase: new Firebase("https://<your-firebase-name>.firebaseio.com/")
});

// MODELS

App.Bar = DS.Model.extend({
  name: DS.attr('string'),
  city: DS.attr('string'),
  deals: DS.hasMany('deal', { async: true })
});

App.Deal = DS.Model.extend({
  title: DS.attr('string'),
  description: DS.attr('string')
});

// ROUTES

App.Router.map(function() {
  this.resource('bars', { path: '/bars' }, function() {
    this.route('new');
  });
  this.resource('bar', { path: '/bar/:bar_id'});
});

App.BarsIndexRoute = Ember.Route.extend({
  model: function() {
    return this.store.findAll('bar');
  }
});

App.BarRoute = Ember.Route.extend({
  model: function(params) {
    return this.store.find('bar', params.bar_id);
  }
});

// CONTROLLERS

App.BarsNewController = Ember.ObjectController.extend({
  init: function() {
    this.set('bar', Ember.Object.create());
  },
  actions: {
    addBar: function() {
      var newBar = this.store.createRecord('bar', {
        name: this.get('bar.name'),
        city: this.get('bar.city')
      });
      newBar.save();
      this.setProperties({
        'bar.name':'',
        'bar.city':''
      });
      this.transitionToRoute('bars');
    }
  }
});

App.BarController = Ember.ObjectController.extend({
  actions: {
    addDeal: function(bar, deal) {
      deal.save().then(function() {
        Promise.cast(bar.get('deals')).then(function(deals) {
          deals.addObject(deal);
          bar.save().then(function() {}, function() {});
        });
      });
    }
  }
});

// COMPONENTS

App.FireBarComponent = Ember.Component.extend({
  actions: {
    addDeal: function() {
      var store = this.get('targetObject.store');
      var deal = store.createRecord('deal', {
        title: this.get('dealTitle'),
        description: this.get('dealDescription')
      });
      this.sendAction('onAddDeal', this.get('bar'), deal);
      this.setProperties({
        dealTitle: '',
        dealDescription: ''
      });
    }
  }
});

index.hbs

  <script type="text/x-handlebars" data-template-name="bars">
    {{outlet}}
  </script>

  <script type="text/x-handlebars" data-template-name="bars/index">
    {{#each bar in arrangedContent}}
    {{#link-to 'bar' bar.id}}{{bar.name}}{{/link-to}}<br/>
    {{/each}}

    {{#link-to 'bars.new'}}Add a new bar{{/link-to}}

    {{outlet}}
  </script>

  <script type="text/x-handlebars" data-template-name="bars/new">
    Add a new bar:
    {{input value=bar.name}}
    {{input value=bar.city}}
    <button {{action "addBar"}}>Add</button>
  </script>

  <script type="text/x-handlebars" data-template-name="components/fire-bar">
    {{bar.name}}<br/>
    {{bar.city}}<br/><br/>

    {{#each deal in bar.deals}}
      {{deal.title}}<br/>
      {{deal.description}}<br/><br/>
    {{/each}}

    Add a deal:<br/>
    {{input value=dealTitle}}<br/>
    {{textarea value=dealDescription}}<br/>

    <button {{action "addDeal"}}>Add Deal</button>
  </script>

  <script type="text/x-handlebars" data-template-name="bar">
    {{fire-bar bar=model onAddDeal="addDeal"}}
  </script>