Rake new_post for Jekyll based on octopress new post

rake_new_post.rb

require "stringex" # gem install stringex

posts_dir       = "_posts"    # directory for blog files
new_post_ext    = "md" 
#extented by can: open editor after creating post, ex. Sublime Text, ia writer
editor          = "Ia Writer"
def get_stdin(message)
  print message
  STDIN.gets.chomp
end
def ask(message, valid_options)
  if valid_options
    answer = get_stdin("#{message} #{valid_options.to_s.gsub(/"/, '').gsub(/, /,'/')} ") while !valid_options.include?(answer)
  else
    answer = get_stdin(message)
  end
  answer
end
# usage rake new_post[my-new-post] or rake new_post['my new post'] or rake new_post (defaults to "new-post")
desc "Begin a new post in #{posts_dir}"
task :new_post, :title do |t, args|
  if args.title
    title = args.title
  else
    title = get_stdin("Enter a title for your post: ")
  end

  mkdir_p "##{posts_dir}"
  filename = "#{posts_dir}/#{Time.now.strftime('%Y-%m-%d')}-#{title.to_url}.#{new_post_ext}"
  if File.exist?(filename)
    abort("rake aborted!") if ask("#{filename} already exists. Do you want to overwrite?", ['y', 'n']) == 'n'
  end
  puts "Creating new post: #{filename}"
  open(filename, 'w') do |post|
    post.puts "---"
    post.puts "layout: post"
    post.puts "title: \"#{title.gsub(/&/,'&')}\""
    post.puts "date: #{Time.now.strftime('%Y-%m-%d %H:%M:%S %z')}"
    post.puts "comments: true"
    post.puts "categories: "
    post.puts "---"
  end

  exec "open -a '#{editor}' #{filename}"
end