add in a free tier (bug 735132)

migrations/366-tier-0.py

@@ -0,0 +1,11 @@
+from decimal import Decimal
+
+from market.models import Price, PriceCurrency
+
+
+def run():
+    tier = Price.objects.create(name='Tier 0', price=Decimal('0'),
+                                active=True)
+    for currency in ['CAD', 'EUR', 'GBP', 'JPY']:
+        PriceCurrency.objects.create(tier=tier, price=Decimal('0'),
+                                     currency=currency)