Add a pagination header

[ci skip]

README.md

@@ -199,6 +199,8 @@ end
 
 Draper infers the decorator used for each item from the name of the collection decorator (`ArticlesDecorator` implies `ArticleDecorator`). If that fails, it falls back to using each item's `decorate` method. Alternatively, you can specify a decorator by overriding the collection decorator's `decorator_class` method.
 
+#### Using pagination
+
 Some pagination gems add methods to `ActiveRecord::Relation`. For example, [Kaminari](https://github.com/amatsuda/kaminari)'s `paginate` helper method requires the collection to implement `current_page`, `total_pages`, and `limit_value`. To expose these on a collection decorator, you can delegate to the `source`:
 
 ```ruby