Add license to gemspec, License as MIT

[bf4]

The runtime dependent gems are licensed as New BSD and MIT.

This gem's license omits a line from the New BSD. I'm not an attorney so I'm not sure what to call it, hence 'modified'

Also see https://github.com/pivotal/LicenseFinder/blob/master/lib/data/licenses/NewBSD.txt and bf4/gemproject#1

[schneems]

Do we need to include licenses for development dependencies? When installed and running as a gem we're not using rake or minitest. I don't think those dependencies are distributed via rubygems and therefore shouldn't go into the license?

I would prefer to make this gem MIT only if possible, though IANAL

[bf4]

I was actually referring to the runtime dependencies. (updated text above)

I don't think the gemspec should include liceneses from dependent gems.

[schneems]

This gem and the other 2 runtime dependent gems should be MIT unless i screwed something up.

[bf4]

See heroku/rails_serve_static_assets#2 though perhaps this one should also be New BSD. I dunno. https://github.com/heroku/rails_12factor/blob/3420a2/LICENSE

[bf4]

Actually, now I'm thinking that I should repush this as BSD-2 Clause and leave it at that since I think BSD/MIT can be assumed into a project without mention.

I posted a question about this in https://groups.google.com/forum/#!topic/rubygems-developers/9hrhhzILY4c

[bf4]

I've since learned a bit, and I think that we can specify just MIT for these as it is compatible with BSD.

[schneems]

Seems good. Can you update the PR?

[bf4]

All MIT all the time, here, heroku/rails_stdout_logging#8 and heroku/rails_serve_static_assets#2

[schneems]

Triple merge! Thanks ❤️

[bf4]

Thank you, as well.