Clarify how to specify a commercial license

[collimarco]

We have a gem distributed under a commercial license (Cuber License).

Now we have specified the license in a file called LICENSE in the root of the Git repository.

However when I run gem build I get a warning, complaining that license is not present in the gemspec.

I see a lot of confusion here, in case of a commercial license (EULA)...

1. Should I keep the license field empty?
2. Should I use Nonstandard for the license field?
3. Should I use Cuber License for the license field?
4. Should I use LicenseRef-LICENSE for the license field?

Every part of your documentation seems to suggest something different and a clarification would be useful for everyone.

[simi]

I'm not SPDX expert, but just follow SPDX specification - https://spdx.github.io/spdx-spec/.

[collimarco]

@simi Which, in practical terms, is case 1, 2, 3, 4 or something else? Can you provide a concrete solution for my scenario above (which is a common case where you have a commercial license)?

[simi]

I have no idea, please consult with SPDX specification and experts. Anyway I don't see anything wrong here with RubyGems.