First make sure to log into your existing Perkville account. Once, there, you'll need to navigate to your email settings by Settings at the top of the page.
Then, click Email on the left hand side of the page. There will be a blank field where you may enter the email address you'd like to add to your account.
Finally, once you confirm that you'd like to merge, we'll send that newly added address a message so that you can confirm the merge. If both accounts had points on them, all points will now be under one account.
Please note that points for registration bonus and birthdays do not transfer over. Registration points are limited to one transaction per account.