Add note to group assignment article

Author: saritai

content/education/manage-coursework-with-github-classroom/create-a-group-assignment.md

@@ -84,6 +84,12 @@ If you've already created a group assignment for the classroom, you can reuse a
 
 #### Choosing a template repository
 
+{% note %}
+
+**Note:** If you provide empty repositories or starter code, the repositories must belong to your organization or be public repositories.
+
+{% endnote  %}
+
 By default, a new assignment will create an empty repository for each team that a student creates. {% data reusables.classroom.you-can-choose-a-template-repository %} For more information about template repositories, see "[Creating a template repository](/github/creating-cloning-and-archiving-repositories/creating-a-template-repository)."
 
 {% data reusables.classroom.assignments-guide-choose-template-repository %}