Forgot about di.xml, who needs that anyway :-D

Author: JeroenBoersma

src/etc/di.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0"?>
+<!--
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+-->
+<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
+    <preference for="Elgentos\Rumvision\Api\ConfigurationInterface" type="Elgentos\Rumvision\Model\Config"/>
+</config>