Add corepos handler method to make arch session

rattail_corepos/app.py

@@ -64,6 +64,10 @@ class CoreHandler(GenericHandler):
         from corepos.db.office_trans import Session
         return Session(**kwargs)
 
+    def make_session_office_arch(self, **kwargs):
+        from corepos.db.office_arch import Session
+        return Session(**kwargs)
+
     def get_office_url(
             self,
             require=False,