fixes GRADE-1205
test plan:
* BEFORE checking out this patchset, make sure you have some assignments
in your database
* check out this patchset and run migrations
* check your database, all assignment rows should be updated so that
grader_comments_visible_to_graders and grader_names_visible_to_final_grader
are true
Change-Id: I2750375838b9cadba490accc190e9abcbd7d9b25
Reviewed-on: https://gerrit.instructure.com/152296
Tested-by: Jenkins
Reviewed-by: Adrian Packel <apackel@instructure.com>
Reviewed-by: Spencer Olson <solson@instructure.com>
QA-Review: Adrian Packel <apackel@instructure.com>
Product-Review: Keith T. Garner <kgarner@instructure.com>
Neil Gupta