Ruby bundle open, set $EDITOR
vi ~/.bashrc or ~/.zshrc or whatever you have:export EDITOR=vim
Because you mentioned Notepad++ I suppose you are working with Windows. You need to set an environment variable called EDITOR containing the path to Notepad++.
If you use zsh on Mac OS X,add this line of code into .zshrc file:
export EDITOR="mvim"
That will make macvim to open the gem.