class Rails::Generators::Base

root, you should use source_root.
by rails to set its generators source root. If you want to customize your source
Returns the default source root for a given generator. This is used internally

def self.default_source_root
  return unless base_name && generator_name
  return unless default_generator_root
  path = File.join(default_generator_root, "templates")
  path if File.exist?(path)
end