Improves developer guide sectioning

Author: LordHepipud

doc/04-Developer-Guide.md

@@ -13,6 +13,12 @@ A detailed overview of functions can be found below
 * [New-IcingaCheck](developerguide/01-New-IcingaCheck.md)
 * [New-IcingaCheckPackage](developerguide/02-New-IcingaCheckPackage.md)
 * [New-IcingaCheckResult](developerguide/03-New-IcingaCheckResult.md)
+
+Example Usage
+---
+
+To get started easier you can find detailed examples for developing modules/integrations/best practices in the following categories:
+
 * [Custom Daemons](developerguide/10-Custom-Daemons.md)
 * [Custom Plugins](developerguide/11-Custom-Plugins.md)
 * [Custom API-Endpoints](developerguide/12-Custom-API-Endpoints.md)