nvm using fish shell

apparently now we have node version managers - and i almost don't want to bother after bad experiences with pipenv / virtualenv but eh..

brew upgrade fish

# install fisher manager & nvm
curl -sL https://git.io/fisher | source && fisher install jorgebucaran/fisher
fisher install jorgebucaran/nvm.fish

# install latest node & persist across terminals in $PATH
nvm install latest
set --universal nvm_default_version latest

et voila