Documented custom web.xml file usage in plugins.

git-svn-id: http://svn.igniterealtime.org/svn/repos/messenger/trunk@1204 b35dd754-fafc-0310-a699-88a17e54d16e

documentation/docs/plugin-dev-guide.html

@@ -210,6 +210,8 @@ looks for plugin development directories in the following format:
      |- web
          |- *.jsp      <- JSPs your plugin uses for the admin console
          |- images/    <- Any images your JSP pages need (optional)
+         |- WEB-INF
+             |- web.xml    <- optional file where custom servlets can be registered
 </pre>
 </fieldset>
 
@@ -220,7 +222,13 @@ build your plugins.</p>
 
 <p>Any JAR files your plugin needs during compilation should be put
 into the <tt>lib</tt> directory. These JAR files will also be copied into
-the plugin's generated <tt>lib</tt> directory as part of the build process.
+the plugin's generated <tt>lib</tt> directory as part of the build process.</p>
+
+<p>If you create a src/web/WEB-INF/web.xml file, any servlets registered there
+will be initialized when the plugin starts up. Only servlet registrations and servlet
+mappings will be honored from the web.xml file. Note: this feature is implemented by
+merging your custom web.xml file into the web.xml file generated by the JSP compilation
+process.</p>
 
 <h2>Implementing Your Plugin</h2>