Empty response for download (likely authentication issue)

[zzolo]

Thanks for (what I hope is) a great project. I am having some troubles just getting some basics running.

I can get the application running locally, but unless the spreadsheet is viewable to the world, all I get is an { } empty object when I go to [id]/download.

For instance, the demo spreadsheet works:
http://localhost:9292/16NZKPy_kyWb_c0jBLo_sTvyoGUrs-ISG7uMDHBMgM5U/download?

But, a test one that is not viewable to the world just gives me back the empty object:
http://localhost:9292/1Pg6ycnWBBUcyb1XaoZttVLffXL40LjSkdZSAclTc3-o/download?

A little debugging, looks like Google is saying the file is not found, which I think its a proxy for permissions issues, but the documentation is not super clear on how that's supposed to work (and Google's API console changes daily).

I have set up a a Google API project and given access to Drive and Google+ and created two credentials, one for GOOGLE_APICLIENT_KEY and the other for GOOGLE_APICLIENT_SERVICEACCOUNT and these are set as environment variables.

I don't know Ruby or Sinatra very well, so maybe I just need to find a way to get a bit more debugging information.

Thanks!