Add explanations

[imliam]

This repository is a good reference to refer back to, but in the past when onboarding new team members who have maybe come from a different framework/ecosystem I've had to explain why some of these conventions are in place to help them understand the choices.

I feel like this would be a good place to explain why some of these conventions and guidelines are in place. Some I can think of off the top of my head:

• Helper functions are named in snake_case because that's what vanilla PHP functions are named like
• Tables are pluralised because they represent multiple instances of data - each instance being an individual row inside the table
• Models are named singularly because they represent a single instance of something that, not a collection of them

Thoughts?

[jannejava]

Good feedback, thanks! I have started to add this now.

[jannejava]

Feel free to add more.