+ belongs_to :user
+ has_many :diary_comments, :include => :user,
+ :conditions => "users.visible = 1",
+ :order => "diary_comments.id"
+
+ validates_presence_of :title, :body
+ validates_length_of :title, :within => 1..255
+ validates_length_of :language, :within => 2..3, :allow_nil => true
+ validates_numericality_of :latitude, :allow_nil => true
+ validates_numericality_of :longitude, :allow_nil => true
+ validates_associated :user