Nicks with underscores are recorded incorrectly

[mapkyca]

e.g _foo_ is saved as foo

[SwartzCr]

this is intentional to work around the case where someone who is having connectivity issues with their server (or hasn't yet authenticated their nick) gets underscores appended to their name.
The code for it is here: https://github.com/shaunagm/WelcomeBot/blob/master/bot.py#L132
though in theory that line should use rstrip instead of replace
So while the nicks.csv will be 'wrong' it shouldn't confuse that user for another one