title: Set custom data- attributes on {{#linkTo}} helper <a> tag
body: <p>How can I set custom <code>data-</code> attribute on the <code>{{#linkTo}}</code> helper? I want use this:</p>
  
  <pre><code>{{#linkTo "foo" data-toggle="dropdown"}}foo{{/linkTo}}
  </code></pre>
  
  <p>and the result should look like this:</p>
  
  <pre><code>&lt;a id="ember323" class="ember-view active"  data-toggle="dropdown" href="#/foo/123"&gt;foo&lt;/a&gt;
  </code></pre>
  
  <p>but it looks like:</p>
  
  <pre><code>&lt;a id="ember323" class="ember-view active"  href="#/foo/123"&gt;foo&lt;/a&gt;
  </code></pre>
  
  <p>How can I do this?</p>