adding counter_cache to comments children and WIPing on the issue

db/migrate/20150811161459_add_children_count_to_comments.rb

@@ -0,0 +1,13 @@
+class AddChildrenCountToComments < ActiveRecord::Migration
+  def up
+    add_column :comments, :children_count, :integer, default: 0
+
+    Comment.find_each do |comment|
+      Comment.reset_counters(comment.id, :children)
+    end
+  end
+
+  def down
+    remove_column :comments, :children_count
+  end
+end