In the [Rails Guide](http://guides.rubyonrails.org/getting_started.html), a partial is built under the name "app/views/comments/\_comment.html.erb" and by placing the below code in the show view of article, Rails knows to iterate through each comment and use the correct partial. How does it know that? I tried changing the partial name to something else besides the singular form of comment and it didn't work. Is this some type of Rails magic I should memorized or is there an explanation? 

```
<%= render @article.comments %>

```

I also tried to render `'comments/comment'` instead and it doesn't work, but why would `'comments/form'` work later on in the guide?