title: Asp Core adding a new way of user registration via Identity
body: <p>I have a question, I have Web Application on Asp Net Core 1.1.0 with the implemented classical Identity model, and OpenIddict for Authorization.</p>
  
  <p>In the classical implementation when registering the user using email / password, I need to realize the possibility of registering also with CodeNumber (numerical sequence length of 15 characters) as login name, and pin code (numeric combination of 4 characters) as a password.</p>
  
  <p>CodeNumber and PinCode will be stored in separate from User Indentity table.</p>
  
  <p>So that users can use two methods to log on to the system</p>
  
  <p>Tell me please how can this be achieved in Asp .Net Core?
  Thank you in advance.</p>