Add rate to google rich snippets / schema.org output

Problem/Motivation

I want to appear the ratings for articles to appear on the google serps.

Steps to reproduce

Proposed resolution

The rate module works perfectly for ratings, but I didn't figued out, what to do, in order to show in the serps.
I Installed the schema.org Module: https://www.drupal.org/project/schema_metatag →
It works for different types like articles, but I dont know how to connect it to the ratings from the rating module.
What I can do, that the aggregateRating appears in the list of the available tokens!
Thanks you!