Move attachment into models/repo/ (#17650)

* Move attachment into models/repo/

* Fix test

* Fix bug

models/issue_lock.go

@@ -37,13 +37,13 @@ func updateIssueLock(opts *IssueLockOptions, lock bool) error {
 		commentType = CommentTypeUnlock
 	}
 
-	sess := db.NewSession(db.DefaultContext)
-	defer sess.Close()
-	if err := sess.Begin(); err != nil {
+	ctx, committer, err := db.TxContext()
+	if err != nil {
 		return err
 	}
+	defer committer.Close()
 
-	if err := updateIssueCols(sess, opts.Issue, "is_locked"); err != nil {
+	if err := updateIssueCols(db.GetEngine(ctx), opts.Issue, "is_locked"); err != nil {
 		return err
 	}
 
@@ -54,9 +54,9 @@ func updateIssueLock(opts *IssueLockOptions, lock bool) error {
 		Type:    commentType,
 		Content: opts.Reason,
 	}
-	if _, err := createComment(sess, opt); err != nil {
+	if _, err := createComment(ctx, opt); err != nil {
 		return err
 	}
 
-	return sess.Commit()
+	return committer.Commit()
 }