update achievement gain date to submission date(not grading date)

1. It makes the leaderboard more fair.
2. Tested properly, it works.
agree too. Implement this small feature will sacrifice some performance.

Do you better ways ?  say done all the query in one time ?

On Mon, Sep 8, 2014 at 11:04 PM, Raymoond Tang <notifications@github.com>
wrote:

> In app/models/user_achievement.rb:
>
> > @@ -4,4 +4,26 @@ class UserAchievement < ActiveRecord::Base
> >    belongs_to :user_course
> >    belongs_to :achievement
> >
> > +  def update_date
>
> I surely agree with @houndci <https://github.com/houndci>
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/Coursemology/coursemology.org/pull/204/files#r17243474>
> .
>