Tag remote in capistrano

deploy.rb

namespace :deploy do
  before :restart, :tag do
    on roles(:app) do
      within "#{deploy_to}/repo" do
        execute :git, "tag -f deployed-to-#{fetch(:stage)}"
        begin
          execute :git, "remote add upstream #{fetch(:repo_url)}"
        rescue
          # The remote might already exist. We don't care if it does.
        end
        execute :git, "push -f upstream deployed-to-#{fetch(:stage)}"
      end
    end
  end
end

staging.rb

set :stage, 'staging'