This is mainly exploratory code.
Add support for automatically creating a review request 

from a pull request.
Step one in integrating pull requests with Reviewboard is 

to first create the review request when a PR happens. 

For now, we provide support only for Github.
To set up the webhook, first make sure your repository 

is linked to Reviewboard. Then, in your repo's settings on Github,

select 'Webhooks' and add 

repos/{repo_num}/github/hooks/close-submitted/.

Make sure to unselect 'Push' and select 'Pull Request' for the event

you'd like to know about.
A new review request should now be created, and the ID of the pull request

that the review request was created from should be displayed on the 

"Information" panel.
Note that if you're testing locally, you should 

set up localtunnel

to foward your request.
Now when you make a commit, a review request should 

be created automatically.
Still to do
* Sync more data like branch info
* Import diffs from the PR
* Link user from Github to Reviewboard (and handle cases where it doesn't exist)