gistfile1.rb

# Partial for 'new comment' derived from http://railscasts.com/episodes/154-polymorphic-association
#
<% form_for [@commentable, Comment.new] do |f| %>
<%= f.error_messages %>
<p>
  <%= f.label :content %><br />
    <%= f.text_area :content %>
</p>
<p><%= f.submit "Submit" %></p>
<% end %>

# Error is: undefined method `comments_path' for #<ActionView::Base:0x2332ec4>

# routes.rb contains (for each model that has comments):
#
map.resources :cities, :has_many => :comments

# and still the default:
#
map.connect ':controller/:action/:id'