Trying to write out files in UTF-8 that TextEdit, Pages, Word and open

input.txt

Danish: æåø
Chinese: 我真累

write_rtf.rb

# encoding: utf-8

require 'rubygems'
require 'rtf'
include RTF

module RTF
  # https://github.com/lfarcy/rtf-extensions
  # Modifies the TextNode class to manage utf8 character strings
  class TextNode < Node
    # This method generates the RTF equivalent for a TextNode object. This
    # method escapes any special sequences that appear in the text.
    def to_rtf
      _text = @text || ''
      _text = _text.gsub("\\", "\\\\\\").gsub("{", "\\{").gsub("}", "\\}")
      _text.unpack('U*').map { |n| n < 128 ? n.chr : n < 256 ? "\\'#{n.to_s(16)}" : "\\u#{n}\\'3f" }.join('')
    end
  end
end

content = ""
f = File.open("input.txt", 'r')
content = f.read
f.close

document = Document.new(Font.new(Font::ROMAN, 'Times New Roman'))

document.paragraph << content

temp_file = File.open("output.rtf", 'w') do |f| 
 f.puts document.to_rtf
end

write_utf8.rb

# encoding: utf-8

puts `file input.txt -I`
content = ""
f = File.open("input.txt", 'r', encoding:'UTF-8')
content = f.read
f.close

temp_file = File.open("output.txt", 'w') do |f| 
 f.puts content
end

f = File.open("output.txt", 'r', encoding:'UTF-8')
puts f.read
puts f.read.encoding
f.close

puts `file output.txt -I`