public async Task <VariantDTO> AddVariant(VariantDTO variantDTO)
{
Variant varianttoAdd = _mapper.Map <Variant>(variantDTO);
IEnumerable <Variant> variants = _variantRepository.GetAll();
Variant existedAuthor = variants.FirstOrDefault
(v => v.QuestionId == varianttoAdd.QuestionId && v.VariantText == varianttoAdd.VariantText);
if (existedAuthor == null)
{
_variantRepository.Insert(varianttoAdd);
_variantRepository.Save();
return(_mapper.Map <VariantDTO>(varianttoAdd));
}
return(null);
}