add uniqueness check for helper checkins
add staff_6 fixtures
Add new student, unassigned assignment to fixtures
add tests for duplicate assigns to helper_assignment
refactor render_missing_params out
Add errors module
include errors module in application controller
increase max method length
re-implement destroy to require reason, close associated assignment
add tests for new destroy method
disable RaiseArgs cop (too strict)
collapse extra line
add routes for helper assignments
more specific rescue
add reassign endpoint
implement helper_assignments endpoints
implement helper_assignments views
test helper_assignments#index
test and debug helper_assignments#show
add create route to helper_assignments