auto restore last attempt training

![screen shot 2014-09-07 at 22 55 35](https://cloud.githubusercontent.com/assets/4983239/4178625/2f710756-369f-11e4-837b-8bb14d17017b.png)

1. If a student haven't done a coding question, his code will be saved and auto restore next time.

2.provide a button if he wants to revert to the template code

3.UI is not beautiful.. need improve
The solution in mission is not suitable here, you need change a lot of
code.  index is what I think best for now without touching other code.

If you don't want  to support I can remove.

On Wed, Sep 10, 2014 at 8:48 PM, Raymoond Tang <notifications@github.com>
wrote:

> In app/views/assessment/training_submissions/_do_coding.html.erb:
>
> >  <div class="path_cm_txtbox cos_code">
> >    <textarea name="ans" id="ans" render="code"
> > +            index="<%= index %>"
>
> I didn't ask you to deal with multiple code area. plus, solution to
> multiple code area won't be this index thing.
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/Coursemology/coursemology.org/pull/203/files#r17358275>
> .
>