NYC Suggested Modifications

[mheadd]

After having some discussions with the NYC Department of Health and Mental Hygiene, I've created a new development branch for the spec and incorporated some changes they recommend.

https://github.com/CityOfPhiladelphia/flu-shot-spec/blob/development/data-format.csv

Changed: facility_id to string (so support alphanumeric identifiers).
Added: data_source: to denote the source of the data on flu shot locations (helpful when data sources are combined across cities).

I wanted to open the door to thoughts, reactions, etc and any suggestions for additional changes to the spec that might be added to the next iterations.

Please add any to as a comment on this issue. Thanks!