Open .Dockerfiles as dockerfile syntax

vimrc

@@ -325,6 +325,8 @@ while c <= 'z'
   let c = nr2char(1+char2nr(c))
 endw
 
+au BufRead,BufNewFile *.Dockerfile setfiletype dockerfile
+
 " Close current window or quit vim if no active windows
 autocmd BufDelete * if len(filter(range(1, bufnr('$')), '!empty(bufname(v:val)) && buflisted(v:val)')) == 1 | q | endif