Goliath app to serve static files

app.rb

require 'goliath'
# require 'goliath/rack/templates'
# require 'haml'
# $:.unshift File.expand_path('../lib', __FILE__)

class StaticAndTemplateFiles < Goliath::API
  # include Goliath::Rack::Templates

  use( Rack::Static,
    :root => Goliath::Application.app_path('public'),
    :urls => ['/'],
    :cache_control => 'public, max-age=3600'
  )

  def response(env)
    [ 200, {"Content-Type" => "text/html"}, [""] ]
  end
end

class App < Goliath::API
  map '/', StaticAndTemplateFiles
end

Procfile

web: bundle exec ruby app.rb -sv -e prod -p $PORT