public static Configuration AddMongoDb(this Configuration configuration, MongoUrl mongoUrl, string collectionName)
        {
            var mongoClient = new MongoClient(mongoUrl);
            var database = mongoClient.GetDatabase(mongoUrl.DatabaseName);
            var collection = database.GetCollection<AppSetting>(collectionName);

            configuration.AddConfigurationSource(new MongoDbSource(collection));

            return configuration;
        }
        public static Configuration AddEnvironmentVariables(this Configuration configuration)
        {
            configuration.AddConfigurationSource(new EnvironmentVariablesSource());

            return configuration;
        }
        public static Configuration AddConfigurationManager(this Configuration configuration)
        {
            configuration.AddConfigurationSource(new ConfigurationManagerSource());

            return configuration;
        }
        public static Configuration AddConfigR(this Configuration configuration, IConfig config)
        {
            configuration.AddConfigurationSource(new ConfigRSource(config));

            return configuration;
        }
        public static Configuration AddInMemory(this Configuration configuration, IDictionary<string, object> appSettings)
        {
            configuration.AddConfigurationSource(new InMemorySource(appSettings));

            return configuration;
        }