Adding a feature called create_extension in init method.

integrations/pgvector/src/haystack_integrations/document_stores/pgvector/document_store.py

@@ -90,6 +90,7 @@ def __init__(
         hnsw_index_name: str = "haystack_hnsw_index",
         hnsw_ef_search: Optional[int] = None,
         keyword_index_name: str = "haystack_keyword_index",
+        create_extension: bool = True,
     ):
         """
         Creates a new PgvectorDocumentStore instance.
@@ -153,6 +154,7 @@ def __init__(
         self.hnsw_ef_search = hnsw_ef_search
         self.keyword_index_name = keyword_index_name
         self.language = language
+        self.create_extension = create_extension
         self._connection = None
         self._cursor = None
         self._dict_cursor = None
@@ -182,6 +184,8 @@ def _create_connection(self):
         conn_str = self.connection_string.resolve_value() or ""
         connection = connect(conn_str)
         connection.autocommit = True
+        if self.create_extension:
+            connection.execute("CREATE EXTENSION IF NOT EXISTS vector")
         register_vector(connection)  # Note: this must be called before creating the cursors.
 
         self._connection = connection