Set active class on Bootstrap Nav-pills

I'm using .nav-pills to create a ui element to select the route in my app like this:

<ul class="nav nav-pills">
    {{#each item in model}}
        <li class="dropdown">
            <a class="dropdown-toggle" href="#" data-toggle="dropdown">
                {{item.name}}<b class="caret"></b>
            </a>
            <ul class="dropdown-menu">
                {{#each child in item.children}}
                    <li>{{#link-to 'child' item child}}{{child.name}}{{/link-to}}</li>
                {{/each}}
            </ul>
        </li>
    {{/each}}
</ul>

It works great, but I can't figure out awhile to get the li.dropdown to have .active. I've tried using link-to helper and setting it to the parent route, but that doesn't seem to work.

Any ideas how to get this to work?