comment controller - excerpt
--------
# GET /comments/new
  # GET /comments/new.xml
  def new
    @comment = @post.comments.build
    @comment.user = @current_user
    respond_to do |format|
      format.html # new.html.erb
      format.xml  { render :xml => @comment }
    end
  end


show.html.erb
----
	<% unless @post.comments.empty? %>
      <% @post.comments.each do |comment| %>
	    <p><%= h comment.body %><br /><small>Posted on <%= h comment.created_at %> by <%= comment.user.login  %></small>
	    </p>
	  <% end %>
	<% end %>
-----

error message i get when this code is in place,
----

NoMethodError in Posts#show

Showing posts/show.html.erb where line #12 raised:

You have a nil object when you didn't expect it!
The error occurred while evaluating nil.login
Extracted source (around line #12):

9: 	<!-- #1 -->
10: 	<% unless @post.comments.empty? %>
11:       <% @post.comments.each do |comment| %>
12: 	    <p><%= h comment.body %><br /><small>Posted on <%= h comment.created_at %> by <%= comment.user.login  %></small>
13: 	    </p>
14: 	  <% end %>
15: 	<% end %>