redmine/db/migrate/019_add_issue_status_position.rb

class AddIssueStatusPosition < ActiveRecord::Migration[4.2]
  def self.up
    add_column :issue_statuses, :position, :integer, :default => 1
    IssueStatus.all.each_with_index {|status, i| status.update_attribute(:position, i+1)}
  end

  def self.down
    remove_column :issue_statuses, :position
  end
end