Update readme

Readme.md

@@ -6,10 +6,22 @@ functions and the wonderful [FaunaDB](https://fauna.com).
 
 ## Motivation
 
-To teach myself how JWTs work and also implement user registration done correctly<sup>\*</sup>.
+I wrote this to teach myself how JWTs work and also implement user
+registration done correctly<sup>\*</sup>.
 
 > <sup>\*</sup>Waiting on https://github.com/zeit/node-file-trace/pull/53 to switch to argon2
 
 ## Implemented functionality
 
-> WIP
+- sign up as new user (or re-sign up as a deleted user which is transparent to the user)
+- login and get JWT with 1 hour expiry (multiple logged in sessions supported)
+- access protected route with only with a valid token
+- logout (kills _all_ logged in sessions and invalidates all tokens for the user)
+- delete user
+
+## Code structure
+
+- `api/*` holds the lambdas that map to each supported route
+- `models/*` holds the models for the entities in the system (User & Token) and some helpers
+- `errors/*` holds the custom error tooling for the codebase
+- `utils/*` hold code structure and type level utilties