bugfix, new check on cat with money, and big update incoming!

data/cat.py

@@ -1,9 +1,10 @@
 class Cat:
-    def __init__(self, name, traits, money=25, inventory={}):
+    def __init__(self, name, traits, money=25, inventory=None):
         self.name = name
         self.traits = traits
         self.money = money
         self.inventory = inventory
+        self.inventory = inventory if inventory is not None else {}
 
     def to_dict(self):
         return vars(self)