The only things not in the database that is can think of are uploads, which the docs you linked describe how to back up before an upgrade.
Vote for NodeBB on Bitnami again!
Seems like you can vote each month again, as I just got this E-Mail
Thank you for voting to add NodeBB to the Bitnami Library in our monthly contest. Unfortunately, they didn't receive enough votes to > > take the top spot last month.
Meet Last Month's Winner - MeteorJS
Still want to see NodeBB in the Bitnami Library? Each month is new chance to win! Vote for NodeBB again this month, and be sure to > > encourage your friends to vote too. You can vote for your favorite app each month until it wins.
The Bitnami Team
So, please vote for NodeBB here