message: shorter cache TTL
diff: @@ -16,7 +16,7 @@ async function cache(ctx, next) {
  await next();
  - ctx.set('Cache-Control', `public, s-maxage=2592000, max-age=86400`);
  + ctx.set('Cache-Control', `public, max-age=${TTL}`);
  ctx.cache[ctx.url] = {
  ts: Date.now(),
  body: ctx.body,
  