In VIM, at the moment when I need to comment out a section of Ruby code:
Try T-comment with Ruby block.
I have T-comment mapped to //.
" Easy commenting
nnoremap // :TComment
vnoremap // :TComment
This allows, from anywhere in a Ruby block, to comment it out with:
var (visual around Ruby)
// (toggle comments)
Note that Ruby blocks has a couple of plugin dependencies that need installing, see my Vimfiles for an example.