migrating from rails 2.3 to rails 3.1 ActiveRecord::UnknownAttributeError: unknown attribute

I am working on migrating an application from rails 2.3 to rails 3.1, most of the things are working but i am getting this error which i am not sure about. The error is

ActiveRecord::UnknownAttributeError: unknown attribute: package_id

Any help on this will be appreciated, Thanks.