Student feedback

Finalised student feedback.

To send email requesting feedback use: **rake feedback:request** (for now you can only do this for the most recent session). 

@todo left:

1. admin side for feedback review
2. not sure if it is done, but in case if it's not: we need populate content to Tutorials table
3. I wrote email template asking for student feedback, I think it needs review :)

P.S. Sorry for delay to finishing this out.