vagrant/website/source/layouts/about.erb

<% wrap_layout :inner do %>
  <% content_for :sidebar do %>
    <div class="docs-sidebar hidden-print affix-top" role="complementary">
      <ul class="nav docs-sidenav">
        <li<%= sidebar_current("about-main") %>>
          <a href="/about.html">About</a>
        </li>
        <li<%= sidebar_current("about-community") %>>
          <a href="/community.html">Community</a>
        </li>
        <li<%= sidebar_current("about-support") %>>
          <a href="/support.html">Support</a>
        </li>
        <li<%= sidebar_current("about-sponsors") %>>
          <a href="/sponsors.html">Sponsors</a>
        </li>
      </ul>
    </div>
  <% end %>

  <%= yield %>
<% end %>