fix authorisation , disallow after after students submit their missions
refactoring grading controller
fix training action paths
fix assessment show page for training
move training submission views to assessment directory
add relation method for_question to answer grading model
update exp transaction callback for grading model, fix update exp transaction method
refactoring, current_step -> step
create training submission grading upon create training submission
refactor training submission controller
add relation method unique_attempts in assessment answer model, this will get all unique answer of student for mcq question
add relation method finalised in assessment question model, this will get all finalised questions of a submission
refactor submission model
refactor mc_auto_grader method in course model
change role related scope to lazy evaluation in user course model
refactor training auto grader, down to lonely 2 methods
refactor partial form of do_mcq and do_coding
use routing constraints to route submission to training correct handler
remove unused training/show.html.erb
fix training submission review