docs(tutorials): fix typo in database table name (#1563)

docs/pages/tutorials/username-and-password/nextjs-app.md

@@ -224,7 +224,7 @@ async function login(_: any, formData: FormData): Promise<ActionResult> {
  }
 
  const existingUser = await db
- .table("username")
+ .table("user")
  .where("username", "=", username.toLowerCase())
  .get();
  if (!existingUser) {