public async Task <Response <string> > AddRoleAsync(AddRoleDto addRoleDto)
        {
            if (await _roleManager.GetRoleAsync(addRoleDto.Name) != null)
            {
                return(Response <string> .Fail("The role already exists. Please try a different one!"));
            }
            var appRole = _mapper.Map <ApplicationRole>(addRoleDto);
            var rs      = await _roleManager.AddRoleAsync(appRole);

            return(rs.Succeeded
                ? Response <string> .Success(appRole.Id, "New role has been created")
                : Response <string> .Fail("Failed to create new role"));
        }