Made PostgreSQL's SchemaEditor._create_index_sql() respect the "sql" argument.
@@ -353,7 +353,7 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
include=None,
expressions=None,
):
- sql = (
+ sql = sql or (
self.sql_create_index
if not concurrently
else self.sql_create_index_concurrently
