def to_hash
      pairs = instance_variables.map do |var|
        [var.to_s.delete('@'), instance_variable_get(var)]
      end
      Hash[pairs]
    end
def to_hash
      pairs = instance_variables.map do |var|
        [var.to_s.delete('@'), instance_variable_get(var)]
      end
      Hash[pairs]
    end
Returns a hash containing all user attributes