Enhance user and audit logging by adding client ID to user scopes and login events

db/migrations/000001_create_users_table.up.sql

@@ -105,6 +105,10 @@ create table user_scopes
         constraint user_scopes_scope_id_fk
             references scopes
             on delete cascade,
+    client_id VARCHAR(26) not null
+        constraint user_scopes_client_id_fk
+            references clients
+            on delete cascade,
     constraint user_scopes_user_id_scope_id_key
-        unique (user_id, scope_id)
+        unique (user_id, scope_id, client_id)
 );

db/migrations/000002_create_audit_table.up.sql

@@ -3,7 +3,7 @@ create table audit_logs
     id        VARCHAR(26)  not null
         constraint audit_logs_pkey
             primary key,
-    user_id   integer,
+    user_id   varchar(26) default null,
     action    varchar(255) not null,
     timestamp timestamptz default current_timestamp,
     details   jsonb