add links

Author: superstes

README.md

@@ -6,6 +6,8 @@ Having variables that hold the IPs of some DNS-record is one of those.
 
 NFTables CAN resolve DNS-records - but will throw an error if the record resolves to more than one IP.. (`Error: Hostname resolves to multiple addresses`)
 
+Links: [NFTables Documentation](https://docs.o-x-l.com/firewall/nftables.html) | [Video in German](https://www.youtube.com/watch?v=bTsElH5FjS8)
+
 ----
 
 ## Other Addons