Disable forcing whitelist attributes from protected attributes

This was the previous functionality since we didn't set anything in the
application configuration. Now when using protected attributes gem, it
sets whitelist to true, forcing us to always declare the accessible
attributes, and this is not the case for the Admin model.

test/rails_app/config/application.rb

@@ -32,6 +32,9 @@ module RailsApp
 
     config.action_mailer.default_url_options = { :host => "localhost:3000" }
 
+    # Disable forcing whitelist attributes from protected attributes.
+    config.active_record.whitelist_attributes = false
+
     # This was used to break devise in some situations
     config.to_prepare do
       Devise::SessionsController.layout "application"