Installing rbenv in a fish environment

rbenv-fish-setup.md

Here we use Homebrew to install rbenv:

1. brew update; and brew install rbenv ruby-build
2. Add ~/.rbenv/shims to your PATH
3. Include the contents of completions/rbenv.fish in your Fish config.
4. Run rbenv install 2.2.2 and rbenv rehash
5. Run rbenv global 2.2.2

Now you can run gem install bundler and bundle install within your Ruby project.

+1 for @tamlyn