doc link

Doc/Sdi/icinga.xml

@@ -23,5 +23,14 @@
       xlink:href="https://www.digitalocean.com/community/tutorials/how-to-install-icinga-and-icinga-web-on-ubuntu-16-04#step-2-%E2%80%93-installing-the-icinga-web-interface">Timezone
       considerations</link>.</para>
     </listitem>
+
+    <listitem>
+      <para><link xlink:href="https://icinga.com/docs/icinga2/latest">Icinga
+      latest documentation.</link></para>
+    </listitem>
   </itemizedlist>
+
+  <para>Configuration validation:</para>
+
+  <screen>icinga2 daemon --validate</screen>
 </chapter>