At GitHub we use a staging environment called review-lab for testing with production data. Deploying a branch to review-lab for testing is one of the best ways to test your work with real production data prior to an actual production deployment.
To make testing on review-lab for extended periods of time easier, you can use the Redirector extension for Chrome to redirect all GitHub.com traffic to your review-lab deploy URL.
Open the extension options panel from the icon in Chrome
In the "From" field, enter: https:\/\/github\.com\/?(.+)?
In the "To" field, enter: https://branchname.review-lab.github.com/$1 where branchname is the name of your branch.
You'll need to remove your rule or simply disable the extension when you want to stop redirecting to your branch.
If you're trying to reach GitHub.com or your review-lab URL but are getting a "This page isn't working" message in your browser, that means your review-lab deploy has gone stale and needs to be redeployed.