Why am I getting undefined method `comments' when using acts_as_commentable_with_threading? <p>On the community's #show page, I get:</p> <blockquote> <p>undefined method `comments'</p> </blockquote> <p>I was wondering why was I get this error?</p> <p><strong>community_topics_controller.rb</strong></p> <pre><code>def show @community_topic = CommunityTopic.find params[:id] @comment = @community_topic.comments.build @community_topic.comments.pop respond_to do |format| format.html # show.html.erb format.json { render json: @community_topic } end end </code></pre> <p><strong>models/community_topic.rb</strong></p> <pre><code>acts_as_commentable </code></pre> <p><strong>views/community_topics/show.html.erb</strong></p> <pre><code>&lt;%= render 'comments/form' %&gt; </code></pre> <p><strong>views/comments/_form.html.erb</strong></p> <pre><code> &lt;div class="field"&gt; &lt;%= f.label :comment %&gt;&lt;br /&gt; &lt;%= f.text_area :comment %&gt; &lt;%= f.hidden_field :commentable_id %&gt; &lt;%= f.hidden_field :commentable_type %&gt; &lt;/div&gt; </code></pre>