Easy screenshots of websites with Ruby

screenshot.rb

# Gemfile
# source 'https://rubygems.org'
# gem 'poltergeist', :require => 'capybara/poltergeist'

require 'bundler'; Bundler.require

include Capybara::DSL

Capybara.register_driver :poltergeist do |app|
  Capybara::Poltergeist::Driver.new(app, :js_errors => false)
end

Capybara.default_driver = :poltergeist
Capybara.javascript_driver = :poltergeist

visit('http://github.com')

save_screenshot('screenshot.png', full: true)

For this you can use the gem gastly.