Golang: Continuous Execution and Simple Plugin/Modular System

How to execute an application continuously and attach multiple modules like website, API, parsers? Using go channels and goroutines, we can achieve a periodic run of the application and stop it during predefined system events (like SIGTERM). To enable modular plugins, we can define our modules contract by using the Go interface and make it possible to attach them to our application.

-----------------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------------

[redux]

Hey man, I just applied for a PHP job, I tried to do the assessment which I failed hard at.
It asked to create a LanguageStudent class with getLanguages method and returns all languages as array, Also a method to addLanguage.
then create a teacher class that inherits LangageStudent and has additional public method, teach(LanguageStudent $student, $language) if teachers know the language it can teach the student and returns true,
This really confused me. I'm only used to using PHP for databases and math :/