JAVA-2592: Update article on AbstractRoutingDatasource (#11320)

Co-authored-by: Dhawal Kapil <dhawalkapil@gmail.com>

persistence-modules/spring-boot-persistence/src/test/resources/application.properties

@@ -4,6 +4,14 @@ spring.datasource.url=jdbc:h2:mem:db;DB_CLOSE_DELAY=-1
 spring.datasource.username=sa
 spring.datasource.password=sa
 
+#database details for CLIENT_A
+client-a.datasource.name=CLIENT_A
+client-a.datasource.script=dsrouting-db.sql
+
+#database details for CLIENT_B
+client-b.datasource.name=CLIENT_B
+client-b.datasource.script=dsrouting-db.sql
+
 # hibernate.X
 hibernate.dialect=org.hibernate.dialect.H2Dialect
 hibernate.show_sql=true

persistence-modules/spring-boot-persistence/src/test/resources/dsrouting-db.sql

@@ -0,0 +1,5 @@
+create table client (
+  id numeric,
+  name  varchar(50),
+  constraint pk_client primary key (id)
+);