Add redirection to /<docid> for Github and GoogleDrive on collaboration branch

[johntyree]

This should really be very simple. The current url ends with a docid. We need to preserve it across redirects.

I've already done this successfully for the Dropbox plugin, but the Github and GoogleDrive plugins are a lot spaghettier and I don't have a solid enough understanding of the how the app is actually designed to do this easily.

I feel like someone who knows what's going on could do this in ten minutes.