在Rails中添加created_at DESC功能

I have an app with post and comment models. In my index action/view, I am iterating through the post and displaying them from most recently created at to oldest created at. My comments are nested inside my posts so in my post show action/view, I want to iterate though the comments and get them to show from most recently created at to oldest created at. I can only seem to get this to work if i create a method in my I have an app with post and comment models. In