Use bigint as user_id type to avoid integer overflow

Author: backjonas

backend/src/db.ts

@@ -11,7 +11,7 @@ await pool.query(
   `CREATE TABLE IF NOT EXISTS transactions(
     id SERIAL,
     created_at TIMESTAMP NOT NULL DEFAULT NOW(),
-    user_id INTEGER,
+    user_id BIGINT,
     user_name TEXT,
     description TEXT,
     amount_cents INTEGER