title: Auth0 database and social connections, unique email addresses
body: <p>Maybe I am missing something here, or this is a flaw in Auth0? I'll give an example of my issue:</p>
  
  <p>Let's say I have my <code>Default App</code> (<strong>client</strong>), hooked up to that I have <code>Username-Password-Authentication</code> (<strong>database connection</strong>) and <code>google-oauth2</code> (<strong>social connection</strong>).</p>
  
  <p>A user comes to my site, signs up via <code>google-oauth2</code> (<strong>social connection</strong>) using <strong>joe@gmail.com</strong>. Once complete, he gets added to my users in Auth0, all great.</p>
  
  <p>A few months later, Joe comes back to my site, and being a busy guy, he forgets he signed up to my site before. This time, he decides to sign up using my custom Email and Password form, that will add the user to the <code>Username-Password-Authentication</code> (<strong>database connection</strong>). so he signs up there using <strong>joe@gmail.com</strong> again, and everything goes well, he is now listed in my user's section in my Auth0 dashboard.</p>
  
  <p>This is the problem, I now have two <strong>joe@gmail.com</strong> accounts, one with <code>google-outh2</code> and one with <code>Username-Password-Authentication</code>. I really can't have this, I need a unique email address, regardless of the ID Auth0 supplies.</p>
  
  <p>Does anyone know how I can make email address in my user section 100% unique? I'd think a rule would do this, but it appears rules only apply AFTER a user has been registered, so I can't run a rule before adding?</p>
  
  <p>the only way I can see doing this right now is make my own checks and delete via the management API, but that is a really long and messy way to do it I feel.</p>
  
  <p>Any help will be appreciated here!</p>
  
  <p>Thanks!</p>