title: Devise: Allow only admin to create users
body: <p>I have a Rails 4 app. It is working with <code>devise 3.2.3</code>. devise is properly integrated. At this point, users can register with email and password, sign in and perform <code>CRUD</code> operations. </p>
  
  <p>Now here is what I would like to do: Instead of having any user to sign up by themselves, I want to create an <code>admin</code>. The <code>admin</code> would retain the responsibility of creating users. I don't want users to sign up by themselves. Basically the admin will create the user, issue them their log-in credentials, and email it to them. </p>
  
  <p>I read <a href="https://stackoverflow.com/questions/19017978/allowing-admins-to-add-users-with-devise">this</a> post and similar ones in SO and in devise wikis to no avail. </p>
  
  <p>I have added a <code>boolean</code> field to <code>users table</code> to identify admin users.</p>
  
  <pre><code>class AddAdminToUser &lt; ActiveRecord::Migration
    def change
      add_column :users, :admin, :boolean, :default =&gt; false
    end
  end
  </code></pre>
  
  <p>I have read about managing users using <code>cancan</code> but I don't know how to use it to achieve my objective 
  The solution i'm looking for would probably require a combination of <code>devise</code> and <code>cancan</code>. </p>
  
  <p>I would appreciate any guidance on this matter. </p>