terraform/website/layouts/downloads.erb

<% wrap_layout :inner do %>
  <% content_for :sidebar do %>
    <ul class="nav docs-sidenav">
      <li<%= sidebar_current("downloads-terraform") %>>
        <a href="/downloads.html">Download Terraform</a>
      </li>

      <li<%= sidebar_current("upgrade-guides") %>>
        <a href="/upgrade-guides/index.html">Upgrade Guides</a>
        <ul class="nav">
          <li<%= sidebar_current("upgrade-guides-0-10") %>>
            <a href="/upgrade-guides/0-10.html">Upgrading to v0.10</a>
          </li>
          <li<%= sidebar_current("upgrade-guides-0-9") %>>
            <a href="/upgrade-guides/0-9.html">Upgrading to v0.9</a>
          </li>
          <li<%= sidebar_current("upgrade-guides-0-8") %>>
            <a href="/upgrade-guides/0-8.html">Upgrading to v0.8</a>
          </li>
          <li<%= sidebar_current("upgrade-guides-0-7") %>>
            <a href="/upgrade-guides/0-7.html">Upgrading to v0.7</a>
          </li>
        </ul>
      </li>
    </ul>
  <% end %>

  <%= yield %>
<% end %>