title: How to change .show() to a .toggle() without duplicating items in my function(how can I refactor)
body: <p>I am currently working in my first backbone.js app.  I made a "show comment" function that renders a view in an underscore.js template and renders it to my view.  The problem is, I want to "toggle" all the comments when a button is clicked, not just "show" commentView. How can I refactor this "showComment" function to not duplicate the current view? The success callback iterates over each comment in the comment view and then renders it. Using toggle, I would like it to just render 1 view, not render the same view, multiple times on each click when clicking toggle.</p>
  
  <p>Example:</p>
  
  <p>User clicks the show comments button, 5 comments are displayed.</p>
  
  <p>User clicks  the show comments button, comments are hidden.</p>
  
  <p>User clicks the show comments button, 10 comments are displayed (the first 5 and since the success function renders a whole new view, the first 5 questions initially displayed are appended to the first 5, so there are 10 total now).</p>
  
  <p>Here is the main function</p>
  
  <pre><code> showComments: function() {
        this.commentsView = this.$el.find(".comments_container");
        this.commentsView.show(); ***INSTEAD OF .show() I CAN USE .TOGGLE() but I get DUPLICATES WHENEVER THE VIEW IS RENDERED ***
        this.commentCollection = new app.CommentList();
        // // debugger;
        var self = this;
        this.commentCollection.fetch({
          data: { question_id: this.$el.attr('question_id') },
          success: function(collection) {
            collection.each(function(comment) {
              var commentView = new app.CommentView({model: comment});
              var html = commentView.render().el;
              self.commentsView.append(html);
            });
          }
        });
  </code></pre>
  
  <p>Here is the backbone Event:</p>
  
  <pre><code>'click .show_comments': 'showComments'
  </code></pre>
  
  <p>Any suggestions would be appreciated, thanks!</p>