def run(self):
        """
        run the plugin
        """
        dockerfile = df_parser(self.workflow.builder.df_path, workflow=self.workflow)
        lines = dockerfile.lines

        # when using final dockerfile, we should use DOCKERFILE_FILENAME
        # otherwise we should use the copied version
        if self.use_final_dockerfile:
            content = 'ADD {0} {1}'.format(DOCKERFILE_FILENAME, self.df_path)
        else:
            content = 'ADD {0} {1}'.format(self.df_name, self.df_path)

        # put it before last instruction
        lines.insert(-1, content + '\n')

        dockerfile.lines = lines

        self.log.info("added %s", self.df_path)

        return content