Why does the crowd cheer everytime a bell rings at the Aviva stadium in Dublin?

I was at a couple of Ireland matches in the Aviva and I always wondered why the bell rings. I heard two stories. One is that it rings when the dart goes through. I don’t think this is very likely. The other is that it rings whenever Scotland score or England concede but I dont think this is right either because I heard it ringing tonight and England and Scotland are not playing.