spa vs ssr vs spg
Single Page Application (SPA): An umbrella term for webpages that are rendered 
on the client and work around AJAX. (Angular, React, ...)
Server Side Rendering (SSR): Server-side rendering (SSR) is an application's 
ability to convert HTML files on the server into a fully rendered HTML 
page for the client. 
Static Site Generator (SSG): A static site generator is a software application
that creates HTML pages from templates or components and a given content source.
