Add closed attribute to group

closes #273 

ermageeeeeeeerd, I worked on the app!
please check pplz. 
ya, I agree, but I was getting sooooo confused about what `person == nil` means, and I know I've gotten really confused about it before. I wrote it in for my own peace of mind and forgot to take it out. 

How would I refactor this? I think it's ugly & that makes me mad. But I can't figure it out. 
HEEEELP MEEEEE TOOOOOBZ.