Update all of your Rubygems for each version of Ruby installed using rbenv.

update-rbenv-rubygems.sh

#! /usr/bin/env bash

set -e

eval "$(rbenv init -)"

for version in `rbenv whence gem`; do
    rbenv shell "$version"
    echo "Updating rubygems for $version"
    gem update --system --no-document --quiet
    echo ""
done