require 'lib/screenshot' class ScreenshotGenerator < ::Middleman::Extension include Capybara::DSL def initialize(app, options_hash={}, &block) super app.before_build do |builder| Screenshot.prepare themes.each do |theme| Screenshot.new(theme).generate_theme_image end puts "Hello World" # builder.run './my_deploy_script.sh' end end end ::Middleman::Extensions.register(:screenshot_generator, ScreenshotGenerator)