[{account_id:"ORG1",progress:[{week:1,goal:5000,raised:2400},{week:2,goal:5100,raised:1000}]}]

db.collection.update({"account_id":"ORG1"},[{"$set":{"progress":{"$function":{"body":"function(prog) {prog[prog.length - 1].raised += 75; return prog}","args":["$progress"],"lang":"js"}}}}])