title: Don't allow a user to change email address using devise with Rails
body: <p>I'm using <code>devise</code> to allow users to log in to a site. The authentication key is set to a username, which is to be unique. Also to be unique is the email address provided. It seems that somehow <code>devise</code> has already figured out that the email address should be unique. So that's good.</p>
  
  <p>Now I want to let people change their passwords. I link over to my <code>edit_user_registration_path</code>, but notice that the user is allowed to change their email address. One option is to set <code>reconfirmable</code> to <code>false</code>... but I don't think I want to allow users to change their email addresses at all.</p>
  
  <p>I think I could just remove the field from the <code>devise</code> view, but theoretically a carefully crafted <code>PUT</code> method could still let them change their email address. Is there a way to stop this field from being mutable? Or is it better to just let the email address be reconfirmable?</p>