Rearrange some imports to ensure rattail.db.model comes last

this is necessary for Continuum versioning

tailbone/app.py

@@ -34,8 +34,7 @@ import sqlalchemy as sa
 import rattail.db
 from rattail.config import make_config
 from rattail.exceptions import ConfigurationError
-from rattail.db.util import get_engines
-from rattail.db.continuum import configure_versioning
+from rattail.db.config import get_engines, configure_versioning
 from rattail.db.types import GPCType
 
 import formalchemy as fa
@@ -44,8 +43,6 @@ from pyramid.authentication import SessionAuthenticationPolicy
 
 import tailbone.db
 from tailbone.auth import TailboneAuthorizationPolicy
-from tailbone.forms import renderers
-from tailbone.forms.alchemy import TemplateEngine
 
 
 def make_rattail_config(settings):
@@ -125,6 +122,9 @@ def make_pyramid_config(settings):
     """
     Make a Pyramid config object from the given settings.
     """
+    from tailbone.forms.alchemy import TemplateEngine
+    from tailbone.forms import renderers
+
     config = Configurator(settings=settings, root_factory=Root)
 
     # Configure user authentication / authorization.