implemented login

README.md

@@ -5,4 +5,17 @@
 * multi-user support
 * bill amount entry
     * monthly bill amount summery
-* build & deploy via docker
+* build & deploy via docker
+
+
+# Authentication
+Authentication consists of the following parts:
+* `next-auth` boilerplate
+    * `middleware.ts` = hooks-up `next-auth` into the page processing pipeline
+        * `auth.config.ts` = defines how user session is to be checked and redirects anonymous user to login page
+    * `auth.ts` = verifies user credentials during the log-in action (i.e. against a database)
+        * exports `auth`, `signIn`, `signOut` actions
+* UI boilerplate
+    * `sidenav.tsx` = implements logout action - calls `signOut` from `auth.ts`
+    * `login-form.tsx` = implements login form
+    * `actions.ts` = handles login-form validation and submition - calls `signIn` from `auth.ts`