Teaspoon + Mocha + Istanbul Coverage

Teaspoon is working showing my tests with Mocha in: localhost:3000/teaspoon/default

I read that I can use Istanbul with Teaspoon for code coverage reports.

I installed with npm istanbul, but I don't know how to run it with teaspoon.

I would like to reach my coverage in localhost:3000/coverage or localhost:3000/teaspoon/default/coverage

What is the configuration? I tried the default one in Teaspoon but is not working:

Teaspoon.setup do |config|
  # Coverage (requires istanbul -- https://github.com/gotwarlost/istanbul)
  config.coverage                      = true
  config.coverage_reports = ['text', 'html', 'cobertura']
  config.coverage_output_dir           = "coverage"
  config.statements_coverage_threshold = 50
  config.functions_coverage_threshold  = 50
  config.branches_coverage_threshold   = 50
  config.lines_coverage_threshold      = 50
end

This configuration is working for me:

Teaspoon.configure do |config|
  config.mount_at = "/teaspoon"

  config.suite do |suite|
    suite.use_framework :mocha
    suite.javascripts += ["support/expect"]
  end

  config.formatters = ["tap"]
  config.color = true
  config.use_coverage = :default

  config.coverage do |coverage|
    coverage.reports = ["html", "cobertura"]
    coverage.output_path = "coverage"
  end
end