Add this to your .vimrc to enable automatic code folding for Ruby comments:
```
" Enable automatic code folding for Ruby
autocmd FileType ruby,eruby
\ set foldmethod=expr |
\ set foldexpr=getline(v:lnum)=~'^\\s*#'
```
Open and close folds with zo and zc.
See **:help folding** for details.
[Automatically fold comments in Vim](http://travisjeffery.com/b/2012/01/automatically-fold-comments-in-vim/)