view db/migrate/048_allow_null_version_effective_date.rb @ 1554:e5c9809534a2 feature_1136

Further fix to that

class AllowNullVersionEffectiveDate < ActiveRecord::Migration
  def self.up
    change_column :versions, :effective_date, :date, :default => nil, :null => true
  end

  def self.down
    raise IrreversibleMigration
  end
end