docs: user and auth entity model

2 files changed, 47 insertions, 2 deletions

diff --git a/docs/book/src/SUMMARY.md b/docs/book/src/SUMMARY.md
index 7390c82..74bc36b 100644
--- a/docs/book/src/SUMMARY.md
+++ b/docs/book/src/SUMMARY.md
@@ -1,3 +1,3 @@
 # Summary
 
-- [Chapter 1](./chapter_1.md)
+- [Entities](./chapter_1.md)
diff --git a/docs/book/src/chapter_1.md b/docs/book/src/chapter_1.md
index b743fda..b638874 100644
--- a/docs/book/src/chapter_1.md
+++ b/docs/book/src/chapter_1.md
@@ -1 +1,46 @@
-# Chapter 1
+# Entities
+
+```mermaid
+erDiagram
+    Account ||--|| Profile : "has"
+    Account ||--o{ Session : "creates"
+    Profile ||--o{ Follow : "follows"
+    Profile ||--o{ Follow : "is followed by"
+    Profile ||--o{ Like : "likes"
+    Profile {
+        string ap_id PK
+        string username
+        string description
+        string inbox
+        string outbox
+        enum type
+        string picture
+        string public_key
+        string private_key
+        timestamp created_at
+        timestamp last_refreshed_at
+    }
+    Account {
+        string ap_id FK
+        string oauth_provider_id PK
+        string oauth_provider_user_id PK
+        string email
+    }
+    Session {
+        string id PK
+        timestamp expires_at
+        string ap_id FK
+    }
+    Follow {
+        string follower_ap_id
+        string following_ap_id
+        timestamp created_at
+    }
+    Like {
+        string ap_id PK
+        string object_id PK
+        timestamp created_at
+    }
+```
+
+Profile.type is an enum supporting the ActivityPub actor type [values](https://www.w3.org/TR/activitystreams-vocabulary/#actor-types)