Redmine BacklogsインストールでUnknown column 'issues.position'

gistfile1.txt

ActiveRecord::StatementInvalid (Mysql::ServerError::BadFieldError: Unknown column 'issues.position' in 'order clause': SELECT `issues`.* FROM `issues`   INNER JOIN `issue_statuses` ON `issue_statuses`.id = `issues`.status_id  WHERE (
          parent_id is NULL
          and project_id = 1
          and tracker_id in (5)
          and fixed_version_id is NULL
          and is_closed = 0)  ORDER BY case when issues.position is null then 1 else 0 end ASC, case when issues.position is NULL then issues.id else issues.position end ASC):
  vendor/plugins/redmine_backlogs/app/models/story.rb:38:in `backlog'
  vendor/plugins/redmine_backlogs/app/models/story.rb:51:in `product_backlog'
  vendor/plugins/redmine_backlogs/app/controllers/rb_master_backlogs_controller.rb:7:in `show'

gistfile2.txt

rake db:migrate:plugins RAILS_ENV=production