document use of @CurrentTimestamp @Version in the Short Guide

Author: gavinking

documentation/src/main/asciidoc/introduction/Entities.adoc

@@ -458,6 +458,18 @@ It's easy to specify that the initial version should be assigned the number `1`
 int version = 1; // the initial version number
 ----
 
+If the version attribute is an `Instant` or datetime, the value assigned to the attribute is generated in the JVM by default.
+
+[TIP]
+====
+If the datetime value should be generated by the database, the `@Version` annotation may be used in conjunction with a <<user-defined-generators,generator annotation>>, for example:
+[source,java]
+----
+@CurrentTimestamp @Version
+LocalDateTime lastUpdated;
+----
+====
+
 Almost every entity which is frequently updated should have a version attribute.
 
 [TIP]