fix: heartbeat entity character length (resolve #415)

migrations/20220930_drop_heartbeats_entity_idx.go

@@ -0,0 +1,24 @@
+package migrations
+
+import (
+	"github.com/muety/wakapi/config"
+	"github.com/muety/wakapi/models"
+	"gorm.io/gorm"
+)
+
+func init() {
+	const name = "20220930-drop_heartbeats_entity_idx"
+	const idxName = "idx_entity"
+
+	f := migrationFunc{
+		name: name,
+		f: func(db *gorm.DB, cfg *config.Config) error {
+			if !db.Migrator().HasTable(&models.Heartbeat{}) || !db.Migrator().HasIndex(&models.Heartbeat{}, idxName) {
+				return nil
+			}
+			return db.Migrator().DropIndex(&models.Heartbeat{}, idxName)
+		},
+	}
+
+	registerPreMigration(f)
+}