group notifications by thread only, not by thread/user

[Fusselwurm]

One notification by thread should be enough, we dont need 20 notifications for different users, when the notification links to a place where you see all the changes in one place anyway.

-> Group by thread, concat user names.

[Fusselwurm]

🤦‍♀️

implementation right now:

• I create one notification for "user a has done x"
• then I push this notification to everyone who is subscribed to the thread in any way

what we'd need here:

• get all people who are subscribed to the thread
• for each, get the respective "users a,b,c did x" notification and update it with another user