Description of changing the log level

Logging.md

@@ -1,3 +1,5 @@
+# Logging to a file
+
 Logging to a file is supported as of 1.5.0. You can specify the path to the log file with the `LOG_FILE` environment variable:
 
 ```sh
@@ -7,4 +9,15 @@ docker run -d --name bitwarden \
 ...
 ```
 
-Note that if you're using the docker image, you'll most likely want to use a file path that is mounted from the host OS (such as the data folder).
+Note that if you're using the docker image, you'll most likely want to use a file path that is mounted from the host OS (such as the data folder).
+
+# Change the log level
+
+To reduce the amount of log messages, you can set the log level to 'critical' (default is 'normal') and disable the extended logging (enabled by default). The [Log level](https://api.rocket.rs/v0.3/rocket/config/enum.LoggingLevel.html) can be adjusted with the environment variable `ROCKET_LOG`. Extended logging can be deactivated by setting the environment variable `EXTENDED_LOGGING` to 'false'.
+
+```sh
+docker run -d --name bitwarden \
+...
+  -e ROCKET_LOG=critical -e EXTENDED_LOGGING=false \
+...
+```