As a bit of an aside, there’s currently one small limitation to DoG, that being that Discourse only allows for posts from a particular site to be placed into a singular category, meaning it’s unable to automatically place the topic of newly-created posts into one of several pre-created categories (each associated with a specific Ghost tier). This is explained in the docs, along with the manual workaround for those whose Ghost sites entail more than a simple subscription setup.
I’d of course offer a PR myself to address this, although as I only know HTML and CSS that’s going to be a little bit impossible. Nonetheless, I imagine that the official Discourse + Ghost integration embed code might utilise something like the following additional line 
