* jan.addProject(homework, { started: false }) // The homework project is not started yet
* jan.setProjects([makedinner, doshopping], { started: true}) // Both shopping and dinner has been started
* jan.setProjects([makedinner, doshopping], { started: true}) // Both shopping and dinner have been started
* ```
*
* If you want to set several target instances, but with different attributes you have to set the attributes on the instance, using a property with the name of the through model: