add user authentication

db/migrations/20260316171605_init_users.sql

@@ -0,0 +1,25 @@
+-- +goose Up
+-- +goose StatementBegin
+CREATE TABLE users (
+  id integer primary key not null,
+  email varchar not null unique,
+  password varchar not null,
+  created_at datetime default current_timestamp,
+  updated_at datetime default current_timestamp
+);
+
+CREATE TRIGGER update_users_updated_at
+AFTER UPDATE ON users
+FOR EACH ROW
+  BEGIN
+    UPDATE users
+    SET updated_at = current_timestamp
+    WHERE id = OLD.id;
+  END;
+-- +goose StatementEnd
+
+-- +goose Down
+-- +goose StatementBegin
+DROP TABLE users;
+-- +goose StatementEnd
+