Mentioning with the method below will only work on version 0.0.10 and above!
Mentioning can be done easily, you can do this by adding @ and followed by the number of the person to be mentioned.
You just need to use a number, you don't need to use a jid. You can combine it with a function that will return a regular number. That way whatscode.js will identify that it's a mention and will mention it if the number exists.