diff --git a/models/migrations/v1_26/v324.go b/models/migrations/v1_26/v324.go
index 5d96bfa3ca..b70de1901b 100644
--- a/models/migrations/v1_26/v324.go
+++ b/models/migrations/v1_26/v324.go
@@ -1,24 +1,15 @@
-// Copyright 2025 The Gitea Authors. All rights reserved.
-// SPDX-License-Identifier: MIT
-
 package v1_26
 
-import (
-	"fmt"
+import "xorm.io/xorm"
 
-	"xorm.io/xorm"
-)
-
-func FixClosedMilestoneCompleteness(x *xorm.Engine) error {
-	// Update all milestones to recalculate completeness with the new logic:
-	// - Closed milestones with 0 issues should show 100%
-	// - All other milestones should calculate based on closed/total ratio
-	_, err := x.Exec("UPDATE `milestone` SET completeness=(CASE WHEN is_closed = ? AND num_issues = 0 THEN 100 ELSE 100*num_closed_issues/(CASE WHEN num_issues > 0 THEN num_issues ELSE 1 END) END)",
-		true,
-	)
-	if err != nil {
-		return fmt.Errorf("error updating milestone completeness: %w", err)
+func AddGroupColumnsToRepositoryTable(x *xorm.Engine) error {
+	type Repository struct {
+		GroupID        int64 `xorm:"UNIQUE(s) INDEX DEFAULT NULL"`
+		GroupSortOrder int
 	}
-
-	return nil
+	_, err := x.SyncWithOptions(xorm.SyncOptions{
+		IgnoreConstrains: false,
+		IgnoreIndices:    false,
+	}, new(Repository))
+	return err
 }
diff --git a/models/repo/repo.go b/models/repo/repo.go
index f0f819c711..7a7edb29fb 100644
--- a/models/repo/repo.go
+++ b/models/repo/repo.go
@@ -220,7 +220,7 @@ type Repository struct {
 	UpdatedUnix  timeutil.TimeStamp `xorm:"INDEX updated"`
 	ArchivedUnix timeutil.TimeStamp `xorm:"DEFAULT 0"`
 
-	GroupID        int64 `xorm:"INDEX DEFAULT NULL"`
+	GroupID        int64 `xorm:"UNIQUE(s) INDEX DEFAULT NULL"`
 	GroupSortOrder int   `xorm:"INDEX"`
 }