Add admin layout with admin navigation

And remove the hacky link list from the dashboard.

app/views/shared/_admin_nav.html.erb

@@ -0,0 +1,18 @@
+<nav id="main-nav">
+  <div class="wrapper">
+    <ul class="pages">
+      <li>
+        <%= link_to "Dashboard", admin_root_path,
+             class: @current_section == :dashboard ? "active" : nil %>
+      </li>
+      <li>
+        <%= link_to "Donations", admin_donations_path,
+              class: @current_section == :donations ? "active" : nil %>
+      </li>
+      <li>
+        <%= link_to "LDAP Users", admin_ldap_users_path,
+              class: @current_section == :ldap_users ? "active" : nil %>
+      </li>
+    </ul>
+  </div>
+</nav>

app/views/shared/_main_nav.html.erb

@@ -3,15 +3,15 @@
     <ul class="pages">
       <li>
         <%= link_to "Services", root_path,
-             class: @current_section == "dashboard" ? "active" : nil %>
+             class: @current_section == :dashboard ? "active" : nil %>
       </li>
       <li>
         <%= link_to "Donations", donations_path,
-              class: @current_section == "contributions" ? "active" : nil %>
+              class: @current_section == :contributions ? "active" : nil %>
       </li>
       <li>
         <%= link_to "Invitations", invitations_path,
-              class: @current_section == "invitations" ? "active" : nil %>
+              class: @current_section == :invitations ? "active" : nil %>
       </li>
     </ul>
   </div>