doc: add ChALkeR as collaborator

Using the non-transliterated name as requested.

The transliteration is "Nikita Skovoroda" (first and last name),
if anyone will want to organize non-ASCII names.

PR-URL: #1927
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Johan Bergström <bugs@bergstroem.nu>
Reviewed-By: Chris Dickinson <christopher.s.dickinson@gmail.com>

Author: ChALkeR

README.md

@@ -327,6 +327,7 @@ information about the governance of the io.js project, see
 * **Oleg Elifantiev** ([@Olegas](https://github.com/Olegas)) <oleg@elifantiev.ru>
 * **Domenic Denicola** ([@domenic](https://github.com/domenic)) <d@domenic.me>
 * **Rich Trott** ([@Trott](https://github.com/Trott)) <rtrott@gmail.com>
+* **Сковорода Никита Андреевич** ([@ChALkeR](https://github.com/ChALkeR)) <chalkerx@gmail.com>
 
 Collaborators follow the [COLLABORATOR_GUIDE.md](./COLLABORATOR_GUIDE.md) in
 maintaining the io.js project.