add sqlite datetime converter

examples/tutorial/flaskr/db.py

@@ -1,4 +1,5 @@
 import sqlite3
+from datetime import datetime
 
 import click
 from flask import current_app
@@ -44,6 +45,9 @@ def init_db_command():
     click.echo("Initialized the database.")
 
 
+sqlite3.register_converter("timestamp", lambda v: datetime.fromisoformat(v.decode()))
+
+
 def init_app(app):
     """Register database functions with the Flask app. This is called by
     the application factory.