Document architecture of Cake

It could be helpful if we document the architecture and parts & pieces of Cake.

This blog post gives a good overview: https://medium.com/hackernoon/dispelling-the-magic-6dc0fdfe476c

Start by reading the linked blog post for its overview of Cake's architecture, then inspect the website's existing documentation structure to identify where an architecture guide could fit. Done means documenting Cake's architecture and its major parts and pieces in the website.

Written by the indexing model from the issue text.