Requirements for rubric

[hcientist]

Probably there are some requirements on the values of the properties of the Rubric, the RubricAssessment, or the RubricAssociation, but these requirements are currently unknown.

Very likely: the RubricAssociation.use_for_grading property should be set to true (perhaps we can investigate this here?).

(related to #2, but that was basically a bug saying this whole script was suddenly not working.)

[Zamua]

All business logic-ish instances of use_for_grading in the repo:

• https://github.com/instructure/canvas-lms/blob/8cf3d457d658740f2f7d34942e9a219e1b62a9c7/app/models/rubric_assessment.rb#L160
• https://github.com/instructure/canvas-lms/blob/83102cef94f63832f510d111aaa98d79d543f97c/lib/cc/assignment_resources.rb#L213
• https://github.com/instructure/canvas-lms/blob/e1a65570c302c1dff50a060d270aa6f00eaab911/app/views/gradebooks/grade_summary.html.erb
• https://github.com/instructure/canvas-lms/blob/e1a65570c302c1dff50a060d270aa6f00eaab911/lib/api/v1/assignment.rb
• https://github.com/instructure/canvas-lms/blob/d291632df378d0650e6c83f0ce310afc79e9017a/app/models/rubric_association.rb#L173