Add API link to index page

Author: Todd Gandee

index.html

@@ -36,6 +36,7 @@ <h1><img src="/assets/images/ember-cli-logo-small-dark.png" alt="Ember CLI" heig
                     </a>
                 </li>
                 {% endfor %}
+                <li class="ectop"><a href="https://ember-cli.com/api/" target="_blank">API</a></li>
                 <li class="ectop"><a href="https://github.com/ember-cli/ember-cli.github.io" target="_blank">Improve the site</a></li>
               </ul>
             </div>