/// <summary>
 /// Caches the user permission.
 /// </summary>
 /// <returns>The user permission.</returns>
 /// <param name="permissionToken">Permission token.</param>
 private async Task CacheUserPermission(PermissionToken permissionToken)
 {
     permissionToken.Id = permissionToken.UserId + "permission";
     await Client.UpsertDocumentAsync(UriFactory.CreateDocumentCollectionUri(databaseId, collectionId), permissionToken);
 }