Go Hexagonal Architecture

This is an example of Hexagonal Architecture in Go. It is a simple project that
I've created to learn more about the Hexagonal Architecture and how to
implement it as best as I can.

I think "Adapter Pattern everywhere" sums up the Hexagonal
Architecture pretty well since there isn't much difference between
interacting with a database and interacting with external applications, they
all follow a similar pattern. In the same way that we might use
an interface and a repository for interacting with a database, we can use
ports and adapters for all of the inputs and the outputs of our application.
and that is what I've wanted to accomplish with this project.