This avoids running a big SQL query which could potentially return a

large number of rows. All we need to check for is existance of AT LEAST
one record. This can be done much faster with LIMIT 1.

lib/rolify/adapters/active_record/role_adapter.rb

@@ -24,7 +24,7 @@ def remove(relation, role_name, resource = nil)
         if roles
           relation.roles.delete(roles)
           roles.each do |role|
-            role.destroy if role.send(ActiveSupport::Inflector.demodulize(user_class).tableize.to_sym).empty?
+            role.destroy if role.send(ActiveSupport::Inflector.demodulize(user_class).tableize.to_sym).limit(1).empty?
           end
         end
         roles