[FEATURE REQUEST] Add contributing guidelines

[Darigov Research]

Having a set of contribution guidelines can be helpful for people to know how you would like contributions/suggestions to be made (like @dongqi0101 in issue #26)

This could be a section in the readme or a specific CONTRIBUTING.md file, see below as an example of what we use on our open source work

## Contributing
Pull requests, corrections, translations & fixes are welcome. Any contributions must be submitted under the same license that the original piece of work (see below). Take a look at any open issues or submit new ones if there is something that needs to be fixed or added.

Watch this video on how to contribute to open source for a complete overview -> [https://www.youtube.com/watch?v=UWA4wyacY2A](https://www.youtube.com/watch?v=UWA4wyacY2A)