Validate and enforce style via CI

script/validate-html

@@ -0,0 +1,27 @@
+#!/usr/bin/env ruby
+
+require 'w3c_validators'
+
+def validator(file)
+  extension = File.extname(file)
+  if extension == '.html'
+    W3CValidators::NuValidator.new
+  elsif extension == '.css'
+    W3CValidators::CSSValidator.new
+  end
+end
+
+def validate(file)
+  puts "Checking #{file}..."
+
+  path = File.expand_path "../_site/#{file}", __dir__
+  results = validator(file).validate_file(path)
+
+  return puts 'Valid!' if results.errors.empty?
+
+  results.errors.each { |err| puts err.to_s }
+  exit 1
+end
+
+validate 'index.html'
+validate File.join 'assets', 'css', 'style.css'