[RUBY]Renamer Thingy

# // Place in folder with files to rename
begin
  append_name = 'Autotile_'
  fileformat = '*.gif'
  files = Dir.glob fileformat
  files.each do |gif|
    next if gif.start_with? append_name
    newname = append_name+gif
    File.rename gif,newname
  end
end