There was a bug with changing timestamps using the topic wrench button. Under some circumstances, a topic was disappearing from the top of the latest tab after changing timestamps. Steps to reproduce:
- Choose a topic on the latest tab (the topic should be created some time ago, but has recent posts)
- Change topic timestamps (for example, move them one day forward):
- Go back to the latest tab and see that topic has disappeared.
This PR fixes this. We were setting topic.bumped_at to the timestamp user specified on the modal. This is incorrect. Instead, we should be setting topic.bumped_at to the created_at timestamp of the last regular (not a whisper and so on) post on the topic.