Show element field collection in JavaFX TableView

I have Employee class:

public class Employee {

    private long id;
    private String name;
    private List<String> days;

   //getters, setters and etc.
}

I know how to display id, name fields in TableView. But how to create a table in which the elements of the collection of an element of the table will also be in cells? I need something like this: