And what a topic they choose to do it too...
What do you mean by ‘succesfully’? Most actual socialist countries are under heavy sanctions/restrictions from capitalists, such as Cuba, Nicaragua, Venezuela. However, they do still provide affordable, and subsidised low-income housing apartments, schooling up to the University level without charge, and freely available healthcare. They also have a degree of planned economy, so unemoloyment isn’t all that high.
I think something like adding movie cataloguing functionality to https://inventaire.io/ could be easier...? They claim to support ActivityPub too as of now...