Add in my validate script for posterity

If you can figure out how to use it, good for you!

build/validate.rb

@@ -0,0 +1,27 @@
+require 'rubygems'
+require 'validator.nu'
+require 'json'
+require 'pp'
+
+files = Dir[File.join(File.dirname(__FILE__), '../exercises/*.html')]
+
+files.each do |file|
+  name = File.basename(file, ".html")
+  if name =~ /^khan-(?:exercise|site)$/
+    puts "skipping #{name}"
+    next
+  end
+
+  doc = File.read(file)
+  doc.gsub!(/<(?!(?:\/?[a-z]+|!DOCTYPE|!--))/, '&lt;')
+  # doc.gsub!(/< /, '&lt;')
+  doc.gsub!(/&(?![a-z])/, '&amp;')
+  doc.gsub!(/ id=".+?"/, "")
+
+  output = JSON.parse(Validator.nu(doc, :host => '127.0.0.1', :port => 8888))
+
+  puts "#{name}" if output["messages"].length > 2
+  output["messages"][2..-1].each do |message|
+    puts "#{message["type"]} on line #{message["lastLine"]}: #{message["message"]}"[0..79]
+  end
+end