feat(docs): report.md update

7project/report.md

@@ -48,6 +48,60 @@ flowchart TB
     client <-- HTTP request/response --> n2
 ```
 
+### Database Schema
+
+```mermaid
+classDiagram
+direction BT
+class alembic_version {
+   varchar(32) version_num
+}
+class categories {
+   varchar(100) name
+   varchar(255) description
+   char(36) user_id
+   int(11) id
+}
+class category_transaction {
+   int(11) category_id
+   int(11) transaction_id
+}
+class oauth_account {
+   char(36) user_id
+   varchar(100) oauth_name
+   varchar(4096) access_token
+   int(11) expires_at
+   varchar(1024) refresh_token
+   varchar(320) account_id
+   varchar(320) account_email
+   char(36) id
+}
+class transaction {
+   blob amount
+   blob description
+   char(36) user_id
+   date date
+   int(11) id
+}
+class user {
+   varchar(100) first_name
+   varchar(100) last_name
+   varchar(320) email
+   varchar(1024) hashed_password
+   tinyint(1) is_active
+   tinyint(1) is_superuser
+   tinyint(1) is_verified
+   longtext config
+   char(36) id
+}
+
+categories  -->  user : user_id -> id
+category_transaction  -->  categories : category_id -> id
+category_transaction  -->  transaction : transaction_id -> id
+oauth_account  -->  user : user_id -> id
+transaction  -->  user : user_id -> id
+```
+
 The workflow works in the following way:
 
 - Client connects to the frontend. After login, frontend automatically fetches the stored transactions from