Trying to see if I'm doing something wrong since bind-attr doesn't appear to be working as expected..

index.html

{{#each}}
    <li {{bind-attr class="isCompleted:completed"}}>
        <input type="checkbox" class="toggle">
        <label>{{title}}</label><button class="destroy"></button>
    </li>
{{/each}}

models-todo.js

Todos.Todo = DS.Model.extend({
    title: DS.attr('string'),
    isComplete: DS.attr('boolean')
});

Todos.Todo.FIXTURES = [
    {
        id: 1,
        title: 'Learn Ember.js',
        isCompleted: true
    },
    {
        id: 2,
        title: '...',
        isCompleted: false
    },
    {
        id: 3,
        title: 'Profit!',
        isCompleted: false
    }
];

Output HTML

<ul id="todo-list">
    <script id="metamorph-3-start" type="text/x-placeholder"></script><script id="metamorph-0-start" type="text/x-placeholder"></script>
        <li class="" data-bindattr-1="1">
            <input type="checkbox" class="toggle">
            <label><script id="metamorph-4-start" type="text/x-placeholder"></script>Learn Ember.js<script id="metamorph-4-end" type="text/x-placeholder"></script></label><button class="destroy"></button>
        </li>
    <script id="metamorph-0-end" type="text/x-placeholder"></script><script id="metamorph-1-start" type="text/x-placeholder"></script>
        <li class="" data-bindattr-2="2">
            <input type="checkbox" class="toggle">
            <label><script id="metamorph-5-start" type="text/x-placeholder"></script>...<script id="metamorph-5-end" type="text/x-placeholder"></script></label><button class="destroy"></button>
        </li>
    <script id="metamorph-1-end" type="text/x-placeholder"></script><script id="metamorph-2-start" type="text/x-placeholder"></script>
        <li class="" data-bindattr-3="3">
            <input type="checkbox" class="toggle">
            <label><script id="metamorph-6-start" type="text/x-placeholder"></script>Profit!<script id="metamorph-6-end" type="text/x-placeholder"></script></label><button class="destroy"></button>
        </li>
    <script id="metamorph-2-end" type="text/x-placeholder"></script><script id="metamorph-3-end" type="text/x-placeholder"></script>
</ul>