PATH=".git/safe/../../bin:$PATH" to your PATH
If you're using bash or zsh:
echo 'PATH=".git/safe/../../bin:$PATH"' >> ~/.$0rc
If you're using fish,
fish_add_path -p ".git/safe/../../bin"
In your Ruby project directory, and any subsequent Ruby project directories, run
Voila! Props to @thorncp for telling me about this and props to the legendary Tim Pope for coming up with it (I believe)