Please add a license to this repo

[rrmerugu]

First, thank you for the project!

Could you please add an explicit LICENSE file to the repo so that it's clear under what terms the content is provided, and under what terms user contributions are licensed?..

I want to use this code in my project invana-studio, but this code is still using vis-network==8.x.x as requirements and i want to be able to update and use this code in my project.