fetch all participants in the course, check list if provided or grab all
fetch all participants in the course, check list if provided or grab all

Cal-CS-61A-Staff/ok,jackzhao-mj/ok,Cal-CS-61A-Staff/ok,jordonwii/ok,Cal-CS-61A-Staff/ok,jordonwii/ok,Cal-CS-61A-Staff/ok,jackzhao-mj/ok,Cal-CS-61A-Staff/ok,jordonwii/ok,jordonwii/ok,jackzhao-mj/ok,jackzhao-mj/ok