title: How to change email address of a user in devise "safely"?
body: <p>By default, <a href="https://github.com/plataformatec/devise" rel="noreferrer">devise</a> uses an email address for sign up and sign in.</p>
  
  <p>But I want that the email address should be allowed to be changed by the user.</p>
  
  <p>If I allow the user to edit the email address, and the user specifies an "incorrect" (i.e. a typo by mistake) email address and then user signs out, <em>and</em> the user also forgets what the typo'ed email was, now the user account is inaccessible by the user!</p>
  
  <p>How to best work around this? (except for creating a separate, unchangeable username field that will always allow user to login)</p>