Print markdown header in vim

.vimrc

" Author:  Dave Hulihan
" Purpose: Prints cute markdown header at the top 
"          of the file, based on filename.

" Print filename header in markdown
function! MarkdownHeader()
  let @a = "#"
  put! a
  put %
  normal ggJ
  s/\.md$//
  normal jdd
endfunction

" map function
command! MarkdownHeader call MarkdownHeader()

" call this on new buffers ending in .md
autocmd BufNewFile *.md MarkdownHeader