terraform-provider-docker/website/docker.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("docs-home") %>>
        <a href="/docs/providers/index.html">All Providers</a>
        </li>

        <li<%= sidebar_current("docs-docker-index") %>>
          <a href="/docs/providers/docker/index.html">Docker Provider</a>
        </li>

        <li<%= sidebar_current("docs-docker-datasource") %>>
          <a href="#">Data Sources</a>
          <ul class="nav nav-visible">
            <li<%= sidebar_current("docs-docker-datasource-registry-image") %>>
              <a href="/docs/providers/docker/d/registry_image.html">docker_registry_image</a>
            </li>
          </ul>
        </li>

        <li<%= sidebar_current("docs-docker-resource") %>>
          <a href="#">Resources</a>
          <ul class="nav nav-visible">
            <li<%= sidebar_current("docs-docker-resource-container") %>>
              <a href="/docs/providers/docker/r/container.html">docker_container</a>
            </li>

            <li<%= sidebar_current("docs-docker-resource-image") %>>
              <a href="/docs/providers/docker/r/image.html">docker_image</a>
            </li>

            <li<%= sidebar_current("docs-docker-resource-network") %>>
              <a href="/docs/providers/docker/r/network.html">docker_network</a>
                        </li>

            <li<%= sidebar_current("docs-docker-resource-volume") %>>
               <a href="/docs/providers/docker/r/volume.html">docker_volume</a>
                        </li>
          </ul>
        </li>
      </ul>
    </div>
  <% end %>

  <%= yield %>
<% end %>