public async Task<Category> CategoryExists(string name)
        {
           var exist= await _context.Categories.FirstOrDefaultAsync(a => a.Name.Trim() == name.Trim());
            return exist;
        }


  [HttpPost]
        public async Task<IActionResult> Post([FromBody]CategoryForPostDto categoryDto)
        {
            var category = mapper.Map<Category>(categoryDto);
            var existingCat = await repo.CategoryExists(categoryDto.Name);
            if (existingCat != null)
            {
                var existingCategoryForGetDto = mapper.Map<CategoryForGetDto>(existingCat);
                return Ok(existingCategoryForGetDto);
            }
            await repo.AddCategory(category);
            await repo.SaveAll();
           var categoryForGetDto = mapper.Map<CategoryForGetDto>(category);
           return Ok(categoryForGetDto);
        }