Updated docs to include deploying providers as modules

docbook/reference/en/en-US/modules/providers.xml

@@ -87,11 +87,46 @@ public class MyEventListenerProvider implements EventListenerProvider {
     <section>
         <title>Registering provider implementations</title>
         <para>
-            Keycloak loads provider implementations from the file-system. By default all JARs inside
+            Keycloak can load provider implementations from JBoss Modules or directly from the file-system. Using Modules
-            <literal>standalone/configuration/providers</literal> are loaded. This is simple, but requires all providers
+            is recommended as you can control exactly what classes are available to your provider. Any providers loaded
-            to share the same library. All provides also inherit all classes from the Keycloak class-loader. In the future
+            from the file-system uses a classloader with the Keycloak classloader as its parent.
-            we'll add support to load providers from modules, which allows better control of class isolation.
         </para>
+
+        <section>
+            <title>Register a provider using Modules</title>
+            <para>
+                To register a provider using Modules first create a module. To do this you have to create a folder inside
+                KEYCLOAK_HOME/modules and add your jar and a <literal>module.xml</literal>. For example to add the event listener
+                sysout example provider create the folder <literal>KEYCLOAK_HOME/modules/org/keycloak/examples/event-sysout/main</literal>.
+                Copy <literal>event-listener-sysout-example.jar</literal> to this folder and create <literal>module.xml</literal>
+                with the following content:
+<programlisting><![CDATA[{
+<?xml version="1.0" encoding="UTF-8"?>
+<module xmlns="urn:jboss:module:1.1" name="org.keycloak.examples.event-sysout">
+    <resources>
+        <resource-root path="event-listener-sysout-example.jar"/>
+    </resources>
+    <dependencies>
+        <module name="org.keycloak.keycloak-core"/>
+        <module name="org.keycloak.keycloak-model-api"/>
+        <module name="org.keycloak.keycloak-events-api"/>
+    </dependencies>
+</module>
+}]]></programlisting>
+                Next you need to register this module with Keycloak. This is done by editing keycloak-server.json and adding
+                it to the providers:
+<programlisting><![CDATA[{
+"providers": [
+    ...
+    "module:org.keycloak.examples.event-sysout"
+]
+}]]></programlisting>
+            </para>
+        </section>
+
+
+        <section>
+            <title>Register a provider using file-system</title>
             <para>
                 To register your provider simply copy the JAR including the ProviderFactory and Provider classes and the
                 provider configuration file to <literal>standalone/configuration/providers</literal>.
@@ -115,6 +150,7 @@ public class MyEventListenerProvider implements EventListenerProvider {
 }]]></programlisting>
             </para>
         </section>
+    </section>
 
     <section>
         <title>Available SPIs</title>