Peewee: fixed sorting for related model columns

examples/peewee/simple.py

@@ -43,7 +43,7 @@ class PostAdmin(peeweemodel.ModelView):
 
     # List of columns that can be sorted. For 'user' column, use User.username as
     # a column.
-    #sortable_columns = ('title', ('user', User.username), 'date')
+    sortable_columns = ('title', ('user', User.email), 'date')
 
     searchable_columns = ('title', User.username)
 

flask_admin/contrib/peeweemodel/view.py

@@ -211,6 +211,13 @@ class ModelView(BaseModelView):
             if isinstance(sort_field, basestring):
                 query = query.order_by((sort_field, sort_desc and 'desc' or 'asc'))
             elif isinstance(sort_field, Field):
+                print sort_field
+
+                if sort_field.model != self.model:
+                    query = self._handle_join(query, sort_field, joins)
+
+                    query = query.order_by((sort_field.model, sort_field.name, sort_desc and 'desc' or 'asc'))
+                else:
                     query = query.order_by((sort_column, sort_desc and 'desc' or 'asc'))
 
         # Pagination