Feature request - open in external editor

Hi there

I have more of a feature request.
I really love how I get to manage gists with Lepton and I use it for making small edits and so on.
But from time to time I need to do more editing on the code, for example run formatting tools like Rubocop on Ruby code.

For use cases like that I'd love to be able to open gists in external editor.
Then it would be nice for Lepton to detect new change and submit it automatically or show some indication in UI that gist has been changed and needs to be synced.

Thanks.