public void SavePackageDefination(PackageDefination packageDefination)
        {
            var alias = packageDefination.Alias;

            if (string.IsNullOrWhiteSpace(alias)) throw new ArgumentException("PackageDefination.Alias is required.");
            if (alias.Contains("/")) throw new ArgumentException("Invalid package alias. package alias cannot contain /");

            var dir = this.Storage.GetDirectory(alias,true);
            this.Storage.PutText(alias + ".package.json",packageDefination.ToJson());
        }