[playframework#56] Docs: document @include. in application.conf

documentation/manual/main.textile

@@ -85,12 +85,22 @@ There are two required configuration files:
 * **application.conf**, the main configuration file for the application. It contains standard configuration options.
 * **routes**, the routes definition file.
 
-p(note). **Tip**
-
 If you need to add some configuration options specific to your application, it’s a good idea to add more options to the **application.conf** file. Configuration options in this file are read programmatically with **Play.configuration.get("propertyName")**.
- 
+
 If any library needs a specific configuration file, try to file it under the conf directory: **this directory is included in the Java ClassPath**.
 
+You can add additional configuration files to the Play configuration by specifying a file name in **application.conf** as the value of a configuration option that has **@include.** at the start of the key. For example, if you define additional MIME types in a **conf/mime-types.conf**
+
+bc. # Web fonts
+mimetype.eot = application/vnd.ms-fontobject
+mimetype.otf = application/octet-stream
+mimetype.ttf = application/octet-stream
+mimetype.woff = application/x-font-woff
+
+you can include them by adding the following line to **application.conf**:
+
+bc. @include.mime = mime-types.conf
+
 h3. The lib directory
 
 This directory contains all standard Java libraries needed by your application. They are automatically added to the Java classpath.