In this section, we will extend the plugin developed in Chapter 3, Planning and Customizing Core Database, and implement the custom post type-related functionality. First, we have to create a new file called class-wpwaf-model-manager.php inside the classes directory of the wpwa-forum plugin.

Most web applications will be larger in scale compared to normal websites or blogs. Implementing all custom post functionalities in one file is not the most ideal or practical thing to do. So, our plan here is to keep the initialization and generic configurations in the main file, while separating each of the custom post types into their own class files. Before we go any further, I would like you to have a look at the updated folder structure of the plugin using the following screenshot:

Now, let's go through each of the new files and folders to identify their roles...