def write_file(name, contents)
      path = File.join(Billy.config.certs_path, name)
      FileUtils.mkdir_p(File.dirname(path))
      File.write(path, contents)
      path
    end
def write_file(name, contents)
      path = File.join(Billy.config.certs_path, name)
      FileUtils.mkdir_p(File.dirname(path))
      File.write(path, contents)
      path
    end
Create/Overwrite a new file with the given name
 and ensure the location is safely created. Pass
 back the resulting path.