Reorder migrations, skip errors if running migration again (#3160)

* Reorder migrations, skip errors if running migration again

* Rename migration file names to match migration version

* Add note about ingored error

models/migrations/v52.go

@@ -0,0 +1,31 @@
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package migrations
+
+import (
+	"fmt"
+	"time"
+
+	"code.gitea.io/gitea/models"
+
+	"github.com/go-xorm/xorm"
+)
+
+func addLFSLock(x *xorm.Engine) error {
+	// LFSLock see models/lfs_lock.go
+	type LFSLock struct {
+		ID      int64        `xorm:"pk autoincr"`
+		RepoID  int64        `xorm:"INDEX NOT NULL"`
+		Owner   *models.User `xorm:"-"`
+		OwnerID int64        `xorm:"INDEX NOT NULL"`
+		Path    string       `xorm:"TEXT"`
+		Created time.Time    `xorm:"created"`
+	}
+
+	if err := x.Sync2(new(LFSLock)); err != nil {
+		return fmt.Errorf("Sync2: %v", err)
+	}
+	return nil
+}