[model] association for has_many :though and attr_accessibles
[migrations] adding attributes to grading_method; model for grading_method_set and join model
[models] grading method set and join model
[spec] for grading method set, join models, and adding new attributes for grading_method
[migration] change default boolean values for grading method set
[validation] validation and testing for presence of name in grading method set
Merge branch 'master' into models_for_grading_methods_and_sets

Conflicts:
	core/app/models/gaku/grading_method.rb