Avoid empty deployments

deploy.rb

  namespace :deploy do
    task :check_changes do
      if current_revision == real_revision
        Capistrano::CLI.ui.say("You don't have any changes to deploy")

        agree = Capistrano::CLI.ui.agree("Continue (Yes, [No]) ") do |q|
          q.default = 'n'
        end

        exit unless agree
      else
        # current_revision depends on current_path
        reset!(:current_path)
        reset!(:current_revision)
        reset!(:real_revision)
      end
    end
  end