Render TOC for legislation draft versions

app/models/legislation/draft_version.rb

@@ -11,6 +11,12 @@ class Legislation::DraftVersion < ActiveRecord::Base
   validates :status, presence: true, inclusion: { in: VALID_STATUSES }
 
   def body_in_html
-    body_html || Redcarpet::Markdown.new(Redcarpet::Render::HTML.new).render(body)
+    renderer = Redcarpet::Render::HTML.new(with_toc_data: true)
+    toc_renderer = Redcarpet::Render::HTML_TOC.new(with_toc_data: true)
+
+    body_html = Redcarpet::Markdown.new(renderer).render(body)
+    toc = Redcarpet::Markdown.new(toc_renderer).render(body)
+
+    return toc, body_html
   end
 end

app/views/legislation/draft_versions/show.html.erb

@@ -6,7 +6,20 @@
     <%= link_to t('.see_changes'), legislation_process_draft_version_changes_path(@process, @draft_version) %>
   </div>
 
-  <div>
-    <%= @draft_version.body_in_html.html_safe %>
+  <% toc, body = @draft_version.body_in_html %>
+
+  <div class="small-12 medium-3 column">
+    <%= toc.html_safe %>
   </div>
+
+  <div class="small-12 medium-9 column">
+    <section data-annotatable-type="legislation_draft_version"
+             data-annotatable-id="<%= @draft_version.id %>">
+
+      <div id="legislation_draft_version_body">
+        <%= body.html_safe %>
+      </div>
+    </section>
+  </div>
+
 </div>