Delete assignments_controller
[routes] Delete contacts from students, use concern instead
[controller] Refactor syllabuses_controller and spec
WIP: Refactor syllabuses
[gem] Update gaku_helpers to 0.0.7
[spec] Add js_edit_link to request_helpers
Clean syllabuses
Merge branch 'mass_cleaning' of github.com:Genshin/GAKUEngine into mass_cleaning