added documentation

it's nothing too novel, okay?

backend/README.md

@@ -8,3 +8,5 @@ This is just an orginizational way of keeping the backend services together (so
 
 - [`public`](./public/README.md) - a RESTful API service
 - [`task`](./task/README.md) - a task scheduler service
+- [`storage`](./storage/README.md) - an internal storage library
+- [`cache`](./cache/README.md) - an internal caching library

backend/cache/README.md

@@ -0,0 +1,7 @@
+# Caching library
+
+also known as `cache`
+
+## What is this?
+
+An internal caching library that houses functionality needed for a key-value database like Redis or Valkey. This was turned into a library because both `public` and `task` needed functionality within.

backend/storage/README.md

@@ -0,0 +1,7 @@
+# Storage library
+
+also known as `storage`
+
+## What is this?
+
+An internal storage library. This was needed because both `public` and `task` needed storage functionality. Additionally, this helps maintainability and avoids duplicate code.