Combine with 2FA example about framework-one-secure-auth

[ddspringle]

I've created a new branch called legacy from the master branch before committing the new code which is breaking.

If you're currently using this code in production and want to upgrade to the latest master then you'll have to reconfigure your database for the additional fields and tables required for 2FA integration, assign existing users phone numbers and provider id's before they can login with 2FA enabled (disabled by default, but the user table, at the very least, will need to be expanded if not using the 2FA option).

[ddspringle]

I've created a legacy branch in the 2FA example code, removed all code from the master branch and updated the README to reflect this code has been rolled into the SA codebase.