class Rails::Railtie::Configuration

config.app_generators.colorize_logging = false

If you want to disable color in console, do:

end
g.test_framework :rspec
g.template_engine :haml
g.orm :datamapper, :migration => true
config.app_generators do |g|

Holds generators configuration:

def app_generators
  @@generators ||= Rails::Configuration::Generators.new
  if block_given?
    yield @@generators
  else
    @@generators
  end
end