add content to the rc script.

def add_to_rc(self, content):
        """
        add content to the rc script.
        """
        if not self.rewrite_config:
            raise DirectoryException("Error! Directory was not intialized w/ rewrite_config.")
        if not self.rc_file:
            self.rc_path, self.rc_file = self.__get_rc_handle(self.root_dir)
        self.rc_file.write(content + '\n')