Submit Shared Google Document for Peer Review

What steps will reproduce the problem?
1. Create a new peer review assessment
2. Have the submit variable be "/" so that you can submit a link
3. have students submit link

What is the expected output? What do you see instead?
I want students to be able to submit google docs for peer review so that they 
can house images and writing in a document off site and still have 
accountability for peer comments on site. This didn't work for two reasons in 
the last course I ran: 1) there was no way to verify the link was shared, and 
2) there was a bug where you could submit a blank amount of info where the link 
needed to be and after submitting there was no way to edit the submission 
making students who wanted to leave comments on work confused because there was 
often times, nothing to comment on. 

What version of the product are you using? On what operating system?
1.5.1

Please provide any additional information below.

Original issue reported on code.google.com by Headco...@gmail.com on 11 Mar 2014 at 6:22

overdrive-diy / course-builder

Submit Shared Google Document for Peer Review #61