You have to have a license to attract contributors. https://choosealicense.com/ and github make it easy; there's zero excuse to not have a license.
Permissive licenses attract the broadest range of contributors, so if you're looking to build a large community, they are the way to go. GPL tends to have a smaller overall, but very strong pool of contributors, so if copyleft makes sense for your technology, by all means use it.
Permissive licenses attract the broadest range of contributors, so if you're looking to build a large community, they are the way to go. GPL tends to have a smaller overall, but very strong pool of contributors, so if copyleft makes sense for your technology, by all means use it.
Just use a license, please.