Fix sqlalchemy not being imported in ext:database

Author: amol-

beaker/ext/database.py

@@ -43,6 +43,8 @@ def __init__(self, namespace, url=None, sa_opts=None, table_name='beaker_cache',
         ``schema_name``
             The schema name to use in the database for the cache.
         """
+        OpenResourceNamespaceManager.__init__(self, namespace)
+        
         if sa_opts is None:
             sa_opts = {}