public override async Task GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context)
        {
            AddCorsHeader(context);

            AppUser user;
            using (AppUserRepository appUserRepository = new AppUserRepository())
            {
                if (await appUserRepository.ValidateUser(context.UserName, context.Password) == false)
                {
                    context.SetError("invalid_grant", "The Username or Password is incorrect.");
                    return;
                }

                user = await appUserRepository.FindUserByUsername(context.UserName);
                //if (!user.IsAuthorized)
                //{
                //    context.SetError("invalid_grant", "This user is not an authorized user. Please contact the site owner.");
                //    return;
                //}

                await appUserRepository.RecordUserLoggedInSuccessfully(user.Id);
            }
            
            AddClaimsToIdentity(context, user);
        }