Please add a license file.

[Joe Block]

I'd like to add this to awesome-zsh-plugins, but it doesn't have a license file.

Please add a license file - if you don't have one in mind, I recommend using choosealicense.com to help choose an appropriate one.

[Gabe Schnall]

@unixorn License added 🎸! Thank you for your work on awesome-zsh-plugins. It’s a really useful reference.