Add notes about logging

- Relates #527

Author: jvalkeal

spring-shell-docs/src/main/asciidoc/using-shell-customization-logging.adoc

@@ -0,0 +1,28 @@
+[[using-shell-customization-logging]]
+=== Logging
+
+On default a _Spring Boot_ application will log messages into a console which
+at minimum is annoying and may also mix output from a shell commands.
+Fortunately there is a simple way to instruct logging changes via boot properties.
+
+Completely silence console logging by defining its pattern as an empty value.
+
+====
+[source, yaml]
+----
+logging:
+  pattern:
+    console:
+----
+====
+
+If you need log from a shell then write those into a file.
+
+====
+[source, yaml]
+----
+logging:
+  file:
+    name: shell.log
+----
+====

spring-shell-docs/src/main/asciidoc/using-shell-customization.adoc

@@ -4,3 +4,5 @@
 This section describes how you can customize the shell.
 
 include::using-shell-customization-styling.adoc[]
+
+include::using-shell-customization-logging.adoc[]