Clicking on any of the bars displays a list of students for that
  particular action (either opened the subsection or attempted the
  problem).
  Students are listed for the sub-sections.
  Students, grade and percent are listed for the problems.
  The on-screen list displays only the first 250 students with
  an overflow message if there are more students than that.
  The csv download lists all students.

Metrics tab shows student data:
  -Count of students opened a subsection
  -Grade distribution per problem

for each section/subsection of the course.

Implemented for both the old and beta dashboard
Controlled by a feature flag 'CLASS_DASHBOARD'
Data is aggregated across all students
Aggregate data computed from courseware_studentmodule