Add nav menu back in, with some custom front matter to explicitly enable pages in the menu.

_includes/header.html

@@ -13,6 +13,14 @@
         </svg>
       </a>
 
+      <div class="trigger">
+        {% for my_page in site.pages %}
+          {% if my_page.title and my_page.in_menu %}
+            <a class="page-link" href="{{ my_page.url | prepend: site.baseurl }}">{{ my_page.title }}</a>
+          {% endif %}
+        {% endfor %}
+      </div>
+      
     </nav>
 
   </div>