Forum:Mastery signs for crafting buildings?

I happened to ask one of my neighbors what a particular item was that was on their farm that I didn't recognize. She told me it was a mastery sign that she got for leveling up to a five star crafting building. I have never heard of this or read about it. Am I missing something? I have had a five star winery for quite awhile now and I never recieved one mastery sign for it. I want one and I'd like to know how to get it since I never got one. If this is so, could someone explain to me what this is about...how to get them and how many there are to get. I'm feeling left out!