Try walking outside, shutting the door, then going back in.
//Repopulates the house following a server reset.
It's all there. What Dorax suggested is sound advice. You may also use the special power on your house key while inside the house to repopulate the furniture after a reset.
It does not automatically populate after a reset, so if you log into the interior of a house after a reset, it will be empty until you do one of those two things.
Note that if for some reason the furniture items were broken/destroyed through some form of damage (i.e. not removed using a furniture tool), neither of these techniques will work and you'll have to wait until the next server reset before the furniture will repopulate.