+ has_many :comments, -> { where(:visible => true).order(:created_at) }, :class_name => "ChangesetComment"
+ has_and_belongs_to_many :subscribers, :class_name => 'User', :join_table => 'changesets_subscribers', :association_foreign_key => 'subscriber_id'
+
+ validates_presence_of :id, :on => :update
+ validates_presence_of :user_id, :created_at, :closed_at, :num_changes
+ validates_uniqueness_of :id
+ validates_numericality_of :id, :on => :update, :integer_only => true
+ validates_numericality_of :min_lat, :max_lat, :min_lon, :max_lat, :allow_nil => true, :integer_only => true
+ validates_numericality_of :user_id, :integer_only => true
+ validates_numericality_of :num_changes, :integer_only => true, :greater_than_or_equal_to => 0
+
+ before_save :update_closed_at
+