terraform/website/source/layouts/heroku.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-heroku-index") %>>
        <a href="/docs/providers/heroku/index.html">Heroku Provider</a>
                </li>

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

                    <li<%= sidebar_current("docs-heroku-resource-app-x") %>>
          <a href="/docs/providers/heroku/r/app.html">heroku_app</a>
                    </li>

                    <li<%= sidebar_current("docs-heroku-resource-app-feature") %>>
          <a href="/docs/providers/heroku/r/app_feature.html">heroku_app_feature</a>
                    </li>

                    <li<%= sidebar_current("docs-heroku-resource-cert") %>>
          <a href="/docs/providers/heroku/r/cert.html">heroku_cert</a>
                    </li>

                    <li<%= sidebar_current("docs-heroku-resource-domain") %>>
          <a href="/docs/providers/heroku/r/domain.html">heroku_domain</a>
                    </li>

                    <li<%= sidebar_current("docs-heroku-resource-drain") %>>
                    <a href="/docs/providers/heroku/r/drain.html">heroku_drain</a>
                    </li>

                    <li<%= sidebar_current("docs-heroku-resource-pipeline-x") %>>
                    <a href="/docs/providers/heroku/r/pipeline.html">heroku_pipeline</a>
                    </li>

                    <li<%= sidebar_current("docs-heroku-resource-pipeline-coupling") %>>
                    <a href="/docs/providers/heroku/r/pipeline_coupling.html">heroku_pipeline_coupling</a>
                    </li>

                    <li<%= sidebar_current("docs-heroku-resource-space") %>>
                    <a href="/docs/providers/heroku/r/space.html">heroku_space</a>
                    </li>
        </ul>
        </li>
      </ul>
    </div>
  <% end %>

  <%= yield %>
  <% end %>