Fix bug with committing transactions in SyncClient.

Psycopg2 needs `commit()` called on connection, otherwise transaction
isn't saved.

Author: andrew-chang-dewitt

db_wrapper/client/sync_client.py

@@ -64,6 +64,8 @@ def _execute_query(
         else:
             db_cursor.execute(query)
 
+        db_cursor.connection.commit()
+
     def execute(
         self,
         query: Query,