gistfile1.txt

  before_save :hash_new_key, :if => :key_not_blank?  
  def key_not_blank?
    !self.key.blank?
  end

  before_save :hash_new_key, :unless => :no_key?  
  def no_key?
    self.key.blank?
  end

  before_save :hash_new_key, :if => :has_key?
  def has_key?
    self.key.present?
  end

  # Imho bättre för enklare saker
  before_save :hash_new_key, :if => Proc.new { |a| a.key.present? }