DOC add documentation on how to disable the transport logs (#183)

Author: leszekhanusz

docs/advanced/logging.rst

@@ -18,4 +18,31 @@ For even more logs, you can set the loglevel at **DEBUG**:
     import logging
     logging.basicConfig(level=logging.DEBUG)
 
+Disabling logs
+--------------
+
+By default, the logs for the transports are quite verbose.
+
+On the **INFO** level, all the messages between the frontend and the backend are logged which can
+be difficult to read especially when it fetches the schema from the transport.
+
+It is possible to disable the logs only for a specific gql transport by setting a higher
+log level for this transport (**WARNING** for example) so that the other logs of your program are not affected.
+
+For this, you should import the logger from the transport file and set the level on this logger.
+
+For the RequestsHTTPTransport:
+
+.. code-block:: python
+
+    from gql.transport.requests import log as requests_logger
+    requests_logger.setLevel(logging.WARNING)
+
+For the WebsocketsTransport:
+
+.. code-block:: python
+
+    from gql.transport.websockets import log as websockets_logger
+    websockets_logger.setLevel(logging.WARNING)
+
 .. _logging: https://docs.python.org/3/howto/logging.html