/Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activerecord-3.0.0/lib/active_record/association_preload.rb:324:in `send': missing attribute: accessory_id (ActiveModel::MissingAttributeError)
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activerecord-3.0.0/lib/active_record/association_preload.rb:324:in `preload_belongs_to_association'
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activerecord-3.0.0/lib/active_record/association_preload.rb:323:in `each'
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activerecord-3.0.0/lib/active_record/association_preload.rb:323:in `preload_belongs_to_association'
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activerecord-3.0.0/lib/active_record/association_preload.rb:121:in `send'
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activerecord-3.0.0/lib/active_record/association_preload.rb:121:in `preload_one_association'
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activesupport-3.0.0/lib/active_support/ordered_hash.rb:126:in `each'
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activesupport-3.0.0/lib/active_support/ordered_hash.rb:126:in `each'
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activerecord-3.0.0/lib/active_record/association_preload.rb:115:in `preload_one_association'
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activerecord-3.0.0/lib/active_record/association_preload.rb:92:in `preload_associations'
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activerecord-3.0.0/lib/active_record/relation.rb:68:in `send'
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activerecord-3.0.0/lib/active_record/relation.rb:68:in `to_a'
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activerecord-3.0.0/lib/active_record/relation.rb:68:in `each'
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activerecord-3.0.0/lib/active_record/relation.rb:68:in `to_a'
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activerecord-3.0.0/lib/active_record/relation/finder_methods.rb:333:in `find_first'
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activerecord-3.0.0/lib/active_record/relation/finder_methods.rb:122:in `first'
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activerecord-3.0.0/lib/active_record/relation/finder_methods.rb:180:in `exists?'
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activerecord-3.0.0/lib/active_record/relation/finder_methods.rb:176:in `exists?'
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activerecord-3.0.0/lib/active_record/base.rb:439:in `__send__'
	from /Users/davidyip/.rvm/gems/ruby-1.8.7-p302/gems/activerecord-3.0.0/lib/active_record/base.rb:439:in `exists?'
	from exists_with_scope.rb:32