public async Task<IHttpActionResult> RemoveLogin(RemoveLoginBindingModel model)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            IdentityResult result;

            if (model.LoginProvider == LocalLoginProvider)
            {
                result = await UserManager.RemovePasswordAsync(User.Identity.GetUserId());
            }
            else
            {
                result = await UserManager.RemoveLoginAsync(User.Identity.GetUserId(),
                    new UserLoginInfo(model.LoginProvider, model.ProviderKey));
            }

            if (!result.Succeeded)
            {
                return GetErrorResult(result);
            }

            return Ok();
        }