title: Sign out specific user with Devise in Rails
body: <p>I have Devise for user authentication.
  I want to sign out a user with a specific id.</p>
  
  <p>in my controller</p>
  
  <pre><code>  def exit
      @user = User.find(5)
      sign_out(@user) # this line here signs out the current_user   
    end
  </code></pre>
  
  <p>The sign out command of devise, even though I pass the @user, it signs out the current_user.
  How can I select a user from the database and sign him out with the devise commands? </p>