What dual use open source license to use to contribute code to the the C2/C3 community

Hi,

I paid someone to write a simple rest API for Google Sheets, that can be used with Google's Application Engine. The code is written in node.js.

This essentially, allows reading and writing to a google sheet given a sheet ID and Range, via C2/C3 AJAX GET and POST.

I want to make the code available as open source to the C2/C3 community and want to know what the best open source license would be, so that it encourages anyone who wants to improve and contribute the improvements back to the code base.

The code should be usable for both private and commercial use.

much appreciating your suggestions,

Dan

I think a BSD license is the best choice to give best flexibility over what can be done with the code (if you are happy for it to be used in commercial software etc.)