title: Devise: Create users without password
body: <p>In our application we have normal users. However, we want to be able to make invitations, to invite certain people. Note that an invitation is directly coupled to a user, as we want to be able to set certain settings for these users already. (We are mitigating clients from our old software to the new). </p>
  
  <p>So:</p>
  
  <ul>
  <li>An admin should be able to create a new user and change its settings.</li>
  <li>When someone follows a link with their <code>invitation_token</code>, they should see a form where they can set a password for their account.</li>
  </ul>
  
  <p>What I am having trouble with, is how to enable the admin to create an user account, bypassing the normal password validation. It would be a horrible solution if a default password would need to be set, as this would create a severe security flaw.</p>
  
  <p>How to create a new User in Devise without providing a password?</p>