Show the entire history of replies above a post when you expend "in reply to"

app/assets/javascripts/discourse/controllers/topic_controller.js

@@ -253,10 +253,29 @@ Discourse.TopicController = Discourse.ObjectController.extend(Discourse.Selected
   },
 
   // Toggle the star on the topic
-  toggleStar: function(e) {
+  toggleStar: function() {
     this.get('content').toggleStar();
   },
 
+  /**
+    Toggle the replies this post is a reply to
+
+    @method showReplyHistory
+  **/
+  toggleReplyHistory: function(post) {
+    var replyHistory = post.get('replyHistory'),
+        topicController = this;
+
+    if (replyHistory.length > 0) {
+      replyHistory.clear();
+    } else {
+      post.set('loadingReplyHistory', true);
+      topicController.get('postStream').findReplyHistory(post).then(function () {
+        post.set('loadingReplyHistory', false);
+      });
+    }
+  },
+
   /**
     Clears the pin from a topic for the currently logged in user