* Automatically subscribe forward users to threads
Update create and update item sql functions to subscribe forward
recipients to the post
When the post is updated, ensure that if a forward user has already unsubscribed, keep it that way. Also ensure that any forward users that are no longer forward users are removed from subscription
* Preserve thread subs from non-fwd users during post edit
* use EXISTS to make a little clearer
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Co-authored-by: Keyan <34140557+huumn@users.noreply.github.com>
Co-authored-by: keyan <keyan.kousha+huumn@gmail.com>