Hey everyone I've got a question about house upgrade. Is it possible to add a house like level 1, then it cost X gold to updrade it. and also when you upgrade it, it will give you like wood, stone, Iron etc.?
For example, you build  a Ironcave, is it then possible to get X iron per minute/hour or something? and if so, how? 

Hope you understand  what I mean.
Thanks, Huezzer!