2. This is a new PR, please review and give feedback

views->posts->index.html.erb

<!-- assume that there is a posts controller with an index method that looks like this:

def index
  @posts = Post.all
end

-->

<ul>
  <% @posts.each do |post| %>
    <li>
      <%= post.body %>
      <ul>
          <% post.comments.each do |comment| %>
            <li><%= comment.body %></li>
          <% end %>
      </ul>
    </li>
  <% end %>
</ul>