Update README.md

Author: billz

README.md

@@ -130,6 +130,7 @@ The following translations are currently maintained by the project:
 - Nederlands
 - 简体中文 (Chinese Simplified)
 - Čeština
+- Русский
 
 If your language is not in the list above, why not [contribute a translation](https://github.com/billz/raspap-webgui/wiki/Translations#contributing-a-translation)? Contributors will receive credit as the original translators.