app.js

var App = Ember.Application.create();

App.ApplicationController = Ember.Controller.extend({
    bag: ['Protein Shake', 'Training Shoes', 'Steroids', 'Insulin Shots'],
    home: [],
    actions: {
        leaveAtHome: function(items) {
            items.forEach(function(item) {
                this.get('bag').removeObject(item);
                this.get('home').addObject(item);
            }.bind(this));
            items.clear();
        },
        bringWithYou: function(items) {
            items.forEach(function(item) {
                this.get('home').removeObject(item);
                this.get('bag').addObject(item);
            }.bind(this));
            items.clear();
        }
    }
});

index.html

<script type="text/x-handlebars" id="application">
    <h2>Bring with you</h2>
    {{view Ember.Select viewName="bag" contentBinding="bag" multiple="multiple"}}
    <button {{action leaveAtHome view.bag.selection}}>Leave items at home, bro</button>
    <hr>
    <h2>Leave at home</h2>
    {{view Ember.Select viewName="home" contentBinding="home" multiple="multiple"}}
    <button {{action bringWithYou view.home.selection}}>DAFUQ, bro. Bring dat shit with you</button>
</script>

<script src="http://cdnjs.cloudflare.com/ajax/libs/jquery/2.0.3/jquery.min.js"></script>
<script src="http://cdnjs.cloudflare.com/ajax/libs/handlebars.js/1.0.0/handlebars.min.js"></script>
<script src="http://cdnjs.cloudflare.com/ajax/libs/ember.js/1.0.0/ember.min.js"></script>
<script src="app.js"></script>