title: Devise error: undefined method `current_sign_in_ip'
body: <p>I just installed Devise into my Rails 4.0.10 app. I wanted by users to be trackable, but I decided I didn't need <code>:current_sign_in_ip</code> and <code>:last_sign_in_ip</code>, so I removed those attributes.</p>
  
  <p>My migration:</p>
  
  <pre><code>  ## Trackable
    t.integer  :sign_in_count, default: 0, null: false
    t.datetime :current_sign_in_at
    t.datetime :last_sign_in_at
    t.string   :initial_ip
    # t.inet     :current_sign_in_ip
    # t.inet     :last_sign_in_ip
  </code></pre>
  
  <p>After I tried to make my first user, I got this error:</p>
  
  <pre><code>NoMethodError in Devise::RegistrationsController#create
  undefined method `current_sign_in_ip' for #&lt;User:xxxxxxxxx&gt;
  </code></pre>
  
  <p>I don't understand why <code>current_sign_in_ip</code> is even being called. Here's the "Create" action, which definitely doesn't include that method:</p>
  
  <pre><code>def create
    build_resource(sign_up_params)
  
    resource.save
    yield resource if block_given?
    if resource.persisted?
      if resource.active_for_authentication?
        set_flash_message :notice, :signed_up if is_flashing_format?
        sign_up(resource_name, resource)
        respond_with resource, location: after_sign_up_path_for(resource)
      else
        set_flash_message :notice, :"signed_up_but_#{resource.inactive_message}" if is_flashing_format?
        expire_data_after_sign_in!
        respond_with resource, location: after_inactive_sign_up_path_for(resource)
      end
    else
      clean_up_passwords resource
      set_minimum_password_length
      respond_with resource
    end
  end
  </code></pre>
  
  <p>Why is <code>current_sign_in_ip</code> even being called at all?</p>