public async Task <IActionResult> GetExchanges([FromRoute] string source)
        {
            if (source.Equals("all"))
            {
                IEnumerable <ExchangeRates> exchangeRates = await _exchangeRateService.GetExchangeRateFromAllSources();

                return(Ok(_mapper.Map <IEnumerable <ExchangeRatesViewModel> >(exchangeRates)));
            }

            return(NotFound());
        }