[DOC] Add Karol Brejna to contributors

Author: manuzhang <owenzhang1990@gmail.com>

Closes #149 from manuzhang/doc.
diff --git a/README.md b/README.md
index 5c0858a..a6beaef 100644
--- a/README.md
+++ b/README.md
@@ -102,6 +102,7 @@
 * [Tomasz Targonski](https://github.com/TomaszT)
 * [Sun Kewei](https://github.com/skw1992)
 * [Gong Yu](https://github.com/pangolulu)
+* [Karol Brejna](https://github.com/karol-brejna-i)
 
 ## Contacts