add comment about the redirect

Author: lunny

routers/web/repo/release.go

@@ -199,6 +199,7 @@ func Releases(ctx *context.Context) {
 
 // TagsList render tags list page
 func TagsList(ctx *context.Context) {
+	// The tag list page will be enabled only when user cannot visit releases page.
 	if ctx.Repo.CanRead(unit.TypeReleases) {
 		ctx.Redirect(fmt.Sprintf("%s/releases", ctx.Repo.RepoLink))
 		return