MarkUsProject/Markus — pull request #1578 by zhangsu (2014-07-16 05:24:51+00:00)
Title: Improve performance of mapping graders to criteria

This continues the pattern of doing bulk operations for mapping graders
to groupings, which solves the n+1 query problem.

Tested:
- rspec
- rake test:units
- rake test:functionals
- Ruby 2.1.2, Postgres