Add tutorials

... and fix logo url to point at wiki

theme/partials/default.hbs

@@ -35,6 +35,7 @@
                     <li class="site-nav-item"><a class="js-ajax-link" title="Governance" href="/Governance">Governance</a></li>
                     <li class="site-nav-item"><a class="js-ajax-link" title="Operations" href="/Operations">Operations</a></li>
                     <li class="site-nav-item"><a class="js-ajax-link" title="Platforms" href="/Platforms">Platforms</a></li>
+                    <li class="site-nav-item"><a class="js-ajax-link" title="Tutorials" href="/Tutorials">Tutorials</a></li>
                     <li class="site-nav-item"><a class="js-ajax-link" title="Join" href="/registration-form">Join</a></li>
                 </ul>
                 <div class="site-title-wrapper">