Automatic Code Folding/Collapsing in Vim for Ruby

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