Does Ruby auto-complete =) Rock on!
Add the following to your .vimrc:
function InsertTabWrapper()
let col = col('.') - 1
if !col || getline('.')[col - 1] !~ '\k'
return "\<tab>"
else
return "\<c-p>"
endif
endfunction
Then use ctrl-p to autocomplete
Many thanks to bougeyman in #rubyonrails