Adds an opener to the registry

        :param opener: Opener object
        :type opener: Opener inherited object

def add(self, opener):
        """Adds an opener to the registry

        :param opener: Opener object
        :type opener: Opener inherited object

        """

        index = len(self.openers)
        self.openers[index] = opener
        for name in opener.names:
            self.registry[name] = index