Why can't I update this row?
cs = c.campaigns_segments.first
=> #<CampaignsSegments segment_id: 1, campaign_id: 1, sortable: nil>
cs.update_attribute(:sortable, 1)
NoMethodError: undefined method `eq' for nil:NilClass from /Library/Ruby/Gems/1.8/gems/activesupport-3.0.0/lib/active_support/whiny_nil.rb:48:in `method_missing' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/persistence.rb:256:in `update' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/locking/optimistic.rb:77:in `update' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/attribute_methods/dirty.rb:68:in `update' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/timestamp.rb:60:in `update' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/callbacks.rb:285:in `update' from /Library/Ruby/Gems/1.8/gems/activesupport-3.0.0/lib/active_support/callbacks.rb:413:in `_run_update_callbacks' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/callbacks.rb:285:in `update' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/persistence.rb:247:in `create_or_update' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/callbacks.rb:277:in `create_or_update' from /Library/Ruby/Gems/1.8/gems/activesupport-3.0.0/lib/active_support/callbacks.rb:423:in `_run_save_callbacks' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/callbacks.rb:277:in `create_or_update' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/persistence.rb:39:in `save' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/validations.rb:43:in `save' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/attribute_methods/dirty.rb:21:in `save' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/transactions.rb:237:in `save' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/transactions.rb:289:in `with_transaction_returning_status' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/connection_adapters/abstract/database_statements.rb:139:in `transaction' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/transactions.rb:204:in `transaction' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/transactions.rb:287:in `with_transaction_returning_status' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/transactions.rb:237:in `save' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/transactions.rb:248:in `rollback_active_record_state!' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/transactions.rb:236:in `save' from /Library/Ruby/Gems/1.8/gems/activerecord-3.0.0/lib/active_record/persistence.rb:117:in `update_attribute'
