Add license to gemspec

[hlascelles]

This gemspec could do with a license so it doesn't show as a failure with tools like license_finder.

I think it is MIT?

[mcmire]

Yup, it's MIT. See https://github.com/mcmire/super_diff/blob/master/LICENSE.

Can you tell me more about what you're trying to do? How are you using license_finder?

[hlascelles]

Yep, sure... There is a field in the gemspec specification that allows a gem to declare its license programmatically. See the details here. The specification says it "should" be present.

The gem license_finder is one of the apps that requires it to be there to tell the license of a project. See here for their description of how/why/where they expect that line.

So if you're open to it, I could make a PR that will add that line (it will literally be a one-liner)?

[mcmire]

Okay, that's fine with me!

[hlascelles]

Opened PR 👍