[core] Clean lib/gaku/testing based on rubocop suggestions
[core] Clean generator based on rubocop suggestions
[core] Clean lib/gaku/grading based on rubocop suggestions
Update rubocop config
[core] Clean based on rubocop suggestions
[frontend] Clean app based on rubocop suggestions
[frontend] Clean spec/controllers based on rubocop suggestions
[frontend] Clean spec/features based on rubocop suggestions
[frontend] Clean based on rubocop suggestions
[archive] Clean based on rubocop suggestions
[testing] Clean based on rubocop suggestions
Clean Rakefile based on rubocop suggestions
Clean based on rubocop suggestions
[archive] Fix failing specs
Merge pull request #311 from Genshin/rubocop_cleaning

Rubocop cleaning