Krzysztof Kotlarek ad3ec5809f
FIX: Dismiss new with better migration (#12062)
Original PR was reverted because of broken migration https://github.com/discourse/discourse/pull/12058

I fixed it by adding this line
```
          AND topics.id IN(SELECT id FROM topics ORDER BY created_at DESC LIMIT :max_new_topics)
```

This time it is left joining a limited amount of topics. I tested it on few databases and it worked quite smooth
2021-02-15 08:50:33 +11:00
..