add export property

Author: reshmabidikar

userguide/platform/includes/killbill-configuration-properties-table.adoc

@@ -1088,5 +1088,15 @@ KB_org_killbill_template_invoiceFormatterFactoryPluginName   |Invoice formatter
 
 |===
 
+=== Export Properties
+
+[options="header",cols="1,1,1,1"]
+|===
+|Property Name/Environment Variable Name   |Description   |Default Value | Configuration Method
+//-------------------------------------------------
+|org.killbill.export.extra.tables.prefix
+/KB_org_killbill_export_extra_tables_prefix   |Prefix of the extra tables that need to be exportted  |aviate_catalog  |System Property/Environment Variable
+|===
+
 [NOTE]
 In case of a Tomcat-based environment, the above properties can be configured as system properties. In case of Docker systems, they can be set via the environment variables mentioned above.