Add upgrade step for column renaming tickets.group

src/onegov/search/upgrade.py

@@ -6,3 +6,11 @@
 from onegov.core.upgrade import upgrade_task
 
 
+@upgrade_task('Rename tickets group column')
+def rename_tickets_group_column(context):
+    if context.has_column('tickets', 'group'):
+        context.operations.alter_column(
+            table_name='tickets',
+            column_name='group',
+            new_column_name='group_title'
+        )