Modules
In Yii2, modules are considered to be mini self-contained software packages containing the complete MVC stack. When paired with an application, modules provide a way to extend applications by adding new features and tools without adding code to our main code base. Consequently, modules are a great way to create and reuse code. When creating applications with Yii2, you'll most likely work with prebuilt models, such as Gii or the Yii2 dev module; however, modules can also be custom applications created specifically to build upon and separate code for a specific purpose. In this section, we'll go over the basic modules in Yii2 as well as cover how to create and implement them within our application.
Module components
Compared to Yii1, modules in Yii2 haven't changed much. At their core, they still consist of the same structure and share many of the same ideas. In Yii2, modules are stored in the modules
directory of our application root and are registered with our application...