rubyzip 2

I would like to see rubyzip 2 support. I have created a fork for that. But I am unable to create a PR:

>  Pull request creation failed. Validation failed: must be a collaborator 

I am not sure if that's intentional. But anyways, here is the branch. The tests pass:

https://github.com/eikes/gtfs/tree/rubyzip-v2