Make postgres backend not work for the moment...

...until I can get a second db-level change in for version 4 (and thus
don't have to worry about creating version 5)

Author: Richard Jones

roundup/backends/back_postgresql.py

@@ -90,6 +90,7 @@ class Database(rdbms_common.Database):
     arg = '%s'
 
     def sql_open_connection(self):
+        raise NotImplementedError, "Please don't use me just yet..."
         db = getattr(self.config, 'POSTGRESQL_DATABASE')
         try:
             conn = psycopg.connect(**db)