added asset to read agency_list.csv and add it to table in gtfs.duckdb

user_code/gtfs/__init__.py

@@ -0,0 +1,2 @@
+# user_code/gtfs/__init__.py
+from .assets import *

user_code/gtfs/assets.py

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+import pandas as pd
+from dagster import asset
+from dagster_duckdb import DuckDBResource
+
+
+@asset
+def agency_list(duckdb: DuckDBResource) -> None:
+    """Load agency list from CSV into DuckDB."""
+
+    # Read the CSV (path is relative to container working directory)
+    df = pd.read_csv('data/gtfs/agency_list.csv')
+
+    # Write to DuckDB
+    with duckdb.get_connection() as conn:
+        conn.execute("""
+            CREATE TABLE IF NOT EXISTS agency_list AS
+            SELECT * FROM df
+        """)

user_code/gtfs/definitions.py

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+from dagster import Definitions
+from dagster_duckdb import DuckDBResource
+from assets import agency_list
+
+defs = Definitions(
+    assets=[agency_list],
+    resources={
+        "duckdb": DuckDBResource(
+            database="data/gtfs/gtfs.duckdb"
+        )
+    }
+)