Ruby on Rails

Unless that the behavior of render is different for collections. In that case how can I do that?

In my controller I'm using:

    def index; render json: Foo.all; end

And here the overrided method:
 
    class Foo
      ...
      def to_json(options = {})
        super({methods: :rank}.merge options)
      end
    end

Calling to_json from the console work as expected. Also raising an exception from the to_json method clearly demonstrate that the to_json isn't called by render.

Thanks