adding sqlalchemy-migrate glue

* add a product and producttype table (addresses #1)
 * add a person table and reference to customers table (fixes #8)
 * use sqlalchemy-migrate's API to setup database and add
   configuration for the sqlalchemy-migrate calls to development.ini
   and the paste_deploy template (fixes #7)


git-svn-id: file:///var/www/wwwusers/usr01/svn/pyalchemybiz/trunk@7 389c73d4-bf09-4d3d-a15e-f94a37d0667a

pyalchemybiz/config/environment.py

@@ -3,6 +3,9 @@ import os
 
 from pylons import config
 from sqlalchemy import engine_from_config
+from sqlalchemy.exceptions import NoSuchTableError
+from migrate.versioning.api import db_version
+
 from pyalchemybiz.model import init_model
 
 import pyalchemybiz.lib.app_globals as app_globals
@@ -35,4 +38,17 @@ def load_environment(global_conf, app_conf):
     # any Pylons config options)
     engine = \
         engine_from_config(config, 'sqlalchemy.default.')
-    init_model(engine)
+
+    try:
+        init_model(engine)
+    except Exception:
+        # special handling for calls in websetup.py
+        import inspect
+        frame = inspect.currentframe()
+        try:
+            functions = [current[3] for current in \
+                             inspect.getouterframes(frame)]
+            if functions[1] != 'setup_config':
+                raise
+        finally:
+            del frame