Register the model with the registry

def register(self, model, index):
        """Register the model with the registry"""
        self.model_to_indexes[model].add(index)
        if not self.connected:
            connections.index_name = {}
            from django.conf import settings
            kwargs = {}
            for name, params in settings.ELASTICSEARCH_CONNECTIONS.items():
                params = copy.deepcopy(params)
                kwargs[name] = params
                connections.index_name[name] = params.pop("index_name")
            connections.configure(**kwargs)
            self.connected = True