JdeRobot Academy is an open source platform that has a collection of exercises to learn robotics in a practical way. Gazebo simulator is the main tool required for testing with ROS. Its latest documentation (including installation recipes, current available exercises and illustrative videos) is on its webpage.
If you are a contributor, please note that we use GitHub Pages and a Jekyll theme (MinimalMistakes) for Academy web page. Feel free to install Jekyll locally, so that, you can test your changes before submitting your pull-request.
Take a look at the contributing guide lines.