If you do currently have user accounts on your website
If you currently offer a user account on your site, we recommend you have an 'Account link' feature.
First off, update your privacy policy to outline that their first and last name (and picture and date of birth, should you choose to add these) will be shared with a trusted third party, NewHaze. You should also email your users about this change, and possibly add an opt-in/out feature.
Secondly, update your users database with three extra fields: newhaze_id (unique), newhaze_token and newhaze_secret
Next, set up a piece of code to run, using users.register for each of your existing users, which registers their basic details with the NewHaze system, and then save the returning values into the relevant fields in the database.
Then add to the registration page on your site the same users.register to run every time somebody signs up. Again, save the returning values to the database.
On the account management page on your site, add a 'Connect with NewHaze' button
When the user has confirmed their account, you can use users.merge and merge their newly connected account (remembering to pass their new request token and request secret in the usual way, and their old newhaze_id. The old newhaze_id, token and secret will be removed, and all of their actions in that account will be transferred to their new account.
Remember to update their new newhaze_id, newhaze_token and newhaze_secret in the database!
Once you've done this, you can have your current site login and the alternative NewHaze login when somebody is creating an account or logging in.