I was browsing stuff related to the game Fate Grand Order when I ran into the word "推し鯖". There's an entire hashtag for it on twitter. https://twitter.com/hashtag/%E6%8E%A8%E3%81%97%E9%AF%96
I've learned that 鯖 is slang for server. But what does 推し mean in this instance? Dictionary says its "fan" or "supporter" of. Does this mean like an unofficial "fan server"