fixed a migration not getting run as it build on false assumptions

server/backend/migration/20230825000000.go

@@ -1,8 +1,11 @@
 package migration
 
 import (
+	"database/sql"
+
 	"github.com/TUM-Dev/Campus-Backend/server/model"
 	"github.com/go-gormigrate/gormigrate/v2"
+	"github.com/guregu/null"
 	"gorm.io/gorm"
 )
 
@@ -12,14 +15,19 @@ func (m TumDBMigrator) migrate20230825000000() *gormigrate.Migration {
 	return &gormigrate.Migration{
 		ID: "20230825000000",
 		Migrate: func(tx *gorm.DB) error {
-			// deactivete the crontab (Rollback deletes this from the enum)
-			// given that previously, not cronjobs for this type existed there is no need to remove offending entries first
+			if err := tx.Delete(&model.Crontab{}, "type = 'chat'").Error; err != nil {
+				return err
+			}
 			return SafeEnumRollback(tx, &model.Crontab{}, "type", "chat")
 		},
 		Rollback: func(tx *gorm.DB) error {
-			// activete the crontab (Migrate adds this from to the enum)
-			// given that previously, not cronjobs for this type existed there is no need to add entries first
-			return SafeEnumMigrate(tx, &model.Crontab{}, "type", "chat")
+			if err := SafeEnumMigrate(tx, &model.Crontab{}, "type", "chat"); err != nil {
+				return err
+			}
+			return tx.Create(&model.Crontab{
+				Interval: 60 * 10, // Every 10 minutes
+				Type:     null.String{NullString: sql.NullString{String: "chat", Valid: true}},
+			}).Error
 		},
 	}
 }

server/backend/migration/20230904000000.go

@@ -16,7 +16,7 @@ func (m TumDBMigrator) migrate20230904000000() *gormigrate.Migration {
 		ID: "20230904000000",
 		Migrate: func(tx *gorm.DB) error {
 			// remove "canteenHeadCount" in the enum
-			if err := tx.Where("type = ?", "ticketsales").Delete(&model.Crontab{}).Error; err != nil {
+			if err := tx.Delete(&model.Crontab{}, "type = 'ticketsales'").Error; err != nil {
 				return err
 			}
 			if err := SafeEnumRollback(tx, model.Crontab{}, "type", "ticketsales"); err != nil {