Improve default behavior for clone operation

copy all fields but uuid, and show flash message(s)

tailbone/views/master.py

@@ -36,7 +36,8 @@ import sqlalchemy as sa
 from sqlalchemy import orm
 
 import sqlalchemy_continuum as continuum
-from sqlalchemy_utils.functions import get_primary_keys
+from sqlalchemy_utils.functions import get_primary_keys, get_columns
+
 
 from rattail.db import model, Session as RattailSession
 from rattail.db.continuum import model_transaction_query
@@ -1110,6 +1111,9 @@ class MasterView(View):
         self.configure_clone_form(form)
         if self.request.method == 'POST' and self.request.POST.get('clone') == 'clone':
             cloned = self.clone_instance(instance)
+            self.request.session.flash("{} has been cloned: {}".format(
+                self.get_model_title(), self.get_instance_title(instance)))
+            self.request.session.flash("(NOTE, you are now viewing the clone!)")
             return self.redirect(self.get_action_url('view', cloned))
         return self.render_to_response('clone', {
             'instance': instance,
@@ -1122,7 +1126,21 @@ class MasterView(View):
         pass
 
     def clone_instance(self, instance):
-        raise NotImplementedError
+        """
+        This method should create and return a *new* instance, which has been
+        "cloned" from the given instance.  Default behavior assumes a typical
+        SQLAlchemy record instance, and the new one has all "column" values
+        copied *except* for the ``'uuid'`` column.
+        """
+        cloned = self.model_class()
+
+        for column in get_columns(instance):
+            if column.name != 'uuid':
+                setattr(cloned, column.name, getattr(instance, column.name))
+
+        self.Session.add(cloned)
+        self.Session.flush()
+        return cloned
 
     def touch(self):
         """