feat(order): Add finalize order functionality

src/allmende_payment_system/database.py

@@ -15,6 +15,18 @@ def create_tables():
 
 
 def ensure_user(user_info: dict, session: Session) -> User:
+    """
+    Retrieve an existing user or create a new one if it doesn't exist.
+    This function queries the database for a user with the given username.
+    If found, it returns the existing user. If not found, it creates a new user
+    with the provided information, adds it to the session, and returns it.
+
+    :param user_info: Dictionary containing user information with keys:
+        - "username" (str): The unique username to search for or create
+        - "display_name" (str, optional): The display name for the new user
+    :param session: SQLAlchemy session for database operations
+    :return: The existing or newly created user object
+    """
     statement = select(User).where(User.username == user_info["username"])
 
     if user := session.scalars(statement).one_or_none():