Counter view now has a "sign" to distinguish between purchases and anti-purchases.

db.py

@@ -75,6 +75,7 @@ class UserProducts(Base):
     user_name = Column(String(10), ForeignKey('users.name'), primary_key=True)
     product_id = Column(Integer, ForeignKey("products.product_id"), primary_key=True)
     count = Column(Integer)
+    sign = Column(Integer)
 
     user = relationship(User, backref=backref('products', order_by=count.desc()), lazy='joined')
     product = relationship(Product, backref="users", lazy='joined')

text_interface/miscmenus.py

@@ -114,7 +114,8 @@ class ShowUserMenu(Menu):
         for ref in user.products:
             product = ref.product
             count = ref.count
-            products.append((product, count))
+            if count > 0:
+                products.append((product, count))
         num_products = len(products)
         if num_products == 0:
             print 'No products purchased yet'