Add README instructions for extending logging_conf

#3

Author: br3ndonland

README.md

@@ -302,8 +302,21 @@ ENV APP_MODULE="package.custom.module:api" WORKERS_PER_CORE="2"
 ### Logging
 
 - `LOGGING_CONF`: Python module containing a logging [configuration dictionary object](https://docs.python.org/3/library/logging.config.html) named `LOGGING_CONFIG`. Can be either a module path (`inboard.logging_conf`) or a file path (`/app/inboard/logging_conf.py`). The `LOGGING_CONFIG` dictionary will be loaded and passed to [`logging.config.dictConfig()`](https://docs.python.org/3/library/logging.config.html). See [br3ndonland/inboard#3](https://github.com/br3ndonland/inboard/pull/3) for more details on logging setup.
+
   - Default: `"inboard.logging_conf"` (the default module provided with inboard)
   - Custom: For a logging config module at `/app/package/custom_logging.py`, `LOGGING_CONF="package.custom_logging"` or `LOGGING_CONF="/app/package/custom_logging.py"`.
+  - If inboard is installed from PyPI with `pip install inboard`, the logging configuration can be easily extended. For example,
+
+    ```py
+    # /app/package/custom_logging.py
+    from inboard import logging_conf
+
+    LOGGING_CONFIG = logging_conf.LOGGING_CONFIG
+    LOGGING_CONFIG["loggers"]["boto3"] = {"propagate": False}
+    LOGGING_CONFIG["loggers"]["botocore"] = {"propagate": False}
+    LOGGING_CONFIG["loggers"]["s3transfer"] = {"propagate": False}
+    ```
+
 - `LOG_COLORS`: Whether or not to color log messages. Currently only supported for `LOG_FORMAT="uvicorn"`.
   - Default:
     - Auto-detected based on [`sys.stdout.isatty()`](https://docs.python.org/3/library/sys.html#sys.stdout).