public async Task Save(IEnumerable <Uri> uris)
        {
            if (uris == null)
            {
                throw new ArgumentNullException(nameof(uris));
            }

            var websites = uris.Select(u => new Website
            {
                Id  = Guid.NewGuid(),
                Uri = u
            });

            await _websiteRepository.Clear().ContinueWith(t => _websiteRepository.Save(websites));
        }