diff --git a/calendar/calendar.go b/calendar/calendar.go
index 7ee03ac..b1ad079 100644
--- a/calendar/calendar.go
+++ b/calendar/calendar.go
@@ -19,7 +19,6 @@ type Calendar struct {
 
 	Name        string `gorm:"index:idx_cal,unique"`
 	Description string
-	ExtLink     string
 
 	Timezone string
 
diff --git a/calendar/util.go b/calendar/util.go
index 1ba8a3a..62dd906 100644
--- a/calendar/util.go
+++ b/calendar/util.go
@@ -2,6 +2,7 @@ package calendar
 
 import (
 	"github.com/gin-gonic/gin"
+	"gorm.io/gorm"
 	"kumoly.io/kumoly/app/auth"
 	"kumoly.io/kumoly/app/errors"
 )
@@ -33,3 +34,18 @@ func HasEventAccess(c *gin.Context, e *Event, cid string) error {
 	}
 	return nil
 }
+
+func ChangeCalGroup(cal_id, to string) error {
+	return db.Transaction(func(tx *gorm.DB) error {
+		affected := tx.Exec(`update events set group_id = (
+			select id from groups where name = ?
+		) where calendar_id = ?`, to, cal_id).RowsAffected
+		if affected == 0 {
+			return errors.ErrorNotFound
+		}
+		tx.Exec(`update events set group_id = (
+			select id from groups where name = ?
+		) where calendar_id = ?`, to, cal_id)
+		return nil
+	})
+}