Make license explicit

[anothermh]

From the README:

"This program is copyrighted free software by NAKAMURA, Hiroshi. You can redistribute it and/or modify it under the same terms of Ruby's license; either the dual license version in 2003, or any later version."

This PR adds the BSD and Ruby licenses as files in the repository and updates the gemspec to reflect that both the Ruby and BSD-2-Clause licenses are valid for this gem.

This will assist in using this gem with other software that tracks software licenses, for example, the papers gem. It will require a release to rubygems.org.

[nahi]

Thanks, interesting gem > papers
I've not tried papers gem but it does not allow "Ruby's" license? That's actually my intention (you can use/distribute this with ruby anytime any condition) so I want to keep "ruby".

Just in case, COPYING of ruby defines that "BSDL or the conditions below" == ruby's license. Ruby or BSD-2-Clause sounds unclear to me.

[nahi]

papers gem seems to have "Ruby" as defaults: https://github.com/newrelic/papers/blob/master/README.md
Just changing "ruby" to "Ruby" is enough?

[anothermh]

GitHub detects licenses using licensee, so changing for papers wouldn't be enough.

Here are some answers to common questions about why it's important to be specific when adding a license: https://github.com/benbalter/licensee/blob/master/docs/what-we-look-at.md#why-not-just-look-at-the-license-field-of-insert-package-manager-here

The current note in the README about the license is insufficient for some business uses, so however you choose to define the license it should be more specific than it is now. The Ruby license has changed over time so it is important to be specific about which Ruby license is being applied (GPL vs BSD), and to include a copy of that specific license.

Using the Ruby license may not be recognized by licensee because it doesn't support dual licenses yet. That's a limitation of licensee and GitHub, though, and shouldn't stop you from using the license you want.

[hrieke]

Adding my vote to a License.md file in the root directory.
It's just considered best practices these days to do that, and mark any borrowed code / 3rd party as such.
(In other words, like writing that term paper in highschool, show your work and references!)

[anothermh]

Turns out that it's faster to find an alternative client that includes a license file than it is to get a license file merged into this repo. I'm closing this after waiting eight years.