Add my name (Xinnan Li) to contributors.md

[xn0611]

This tutorial is awesome. Will definitely recommend this to my friends. Thanks a ton!

[Roshanjossey]

@xn0611, I'm quite elated about your pull request. I wanna evolve this project to addresses various problems faced by first-time contributors. I'd love to learn about your journey in open source community, the problems, pain points you had etc.
Could you explain how you felt when you went through the tutorial, made a pull request and learned that I merged it?


We’ve recently added Facebook share and tweet feature to our web app. Could you please go to https://roshanjossey.github.io/first-contributions/#social-share and share your first contribution to open source? 
Also, check out projects with easy issues while you’re there.

[xn0611]

@Roshanjossey Its not my first pr. Maybe me feeling it super clear does not apply to first timers necessarily. I was trying to play around with Gitkraken and all these work for me very well. However, I have many friends who have never used git before. I would love to suggest them to try this out. Also, I'd love to contribute to this amazing tutorial so that it can help more people.

Thanks a lot for your efforts on this. I would take a look at the other link you sent.

Cheers!

[Roshanjossey]

@xn0611, We also have a slack team to help/mentor people trying to contribute to open source projects.
You could help others who are looking for mentors there.
You can join the team by going to https://firstcontributions.herokuapp.com