/// <summary>
/// obtains a user roles
/// </summary>
/// <param name="session">framework that establishes communication between the application and the database</param>
/// <param name="context">HTTP context</param>
/// <returns>returns a list of roles</returns>
public static IEnumerable <Rol> GetRols(ISession session, HttpContextBase context)
{
RolRepository objrol = new RolRepository(session);
int userId = (context.User as CustomPrincipal).UserId;
return(objrol.GetRols(userId));
}