Class description and chat feature

Adding a class description field would be super helpful for teachers and students. Instructors can write a short description of the class, link to relevant resources, put their email, outline grading and integrity policy, etc, much like a college course syllabus description. A class chat too might be useful.

And thank you so much for the amazing new teacher tools updates: assigning course and unit mastery from the course/unit page directly, assigning course challenges, new colour-coded skills reports, etc. I also love the new learner-friendly features, like classroom courses, in addition to assignments and mastery goals, and the visual progress that brings Missions nostalgia.