This is a stash in the meantime i get a better way to do.
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more ~/.config/fish/functions/rvm.fish
curl --create-dirs -o ~/.config/fish/functions/rvm.fish https://raw.github.com/lunks/fish-nuggets/master/functions/rvm.fish
curl -sSL https://get.rvm.io | bash -s stable
rvm install 2.1
rvm use 2.1