create a table for README.md from ansible var files

yaml2readme.rb

#!/usr/bin/ruby
require 'psych'
require 'pathname'

def escape(string)
  string.gsub(/_/, '\_')
end

def mdfy_default(file)
  yaml = Psych.load_file(file)
  puts '| Variable | Description | Default |'
  puts '|----------|-------------|---------|'
  yaml.each do |e|
    k = e[0]
    v = e[1].to_s.empty? ? '""' : e[1].to_s
    puts "| %s | | %s |" % [ escape(k), escape(v) ]
  end
end

def mdfy_var(file)
  yaml = Psych.load_file(file)
  puts "## #{ file.basename.to_s.split('.').first }"
  puts ''
  puts '| Variable | Default |'
  puts '|----------|---------|'
  yaml.each do |e|
    k = e[0]
    v = e[1].to_s.empty? ? '""' : e[1].to_s
    puts "| %s | %s |" % [ escape(k), escape(v) ]
  end
end

file = Pathname.new('.') + 'defaults' + 'main.yml'

mdfy_default(file)
puts ''

var_dir = Pathname.new('.') + 'vars'
var_files = var_dir.children.select { |c| c.file? }
var_files.sort.each do |f|
  mdfy_var(f)
  puts ''
  puts 'Created by [yaml2readme.rb](https://gist.github.com/trombik/b2df709657c08d845b1d3b3916e592d3)'
end