Redmine/db/migrate/097_add_view_wiki_edits_permission.rb

class AddViewWikiEditsPermission < ActiveRecord::Migration
  def self.up
	Role.find(:all).each do |r|
	  r.add_permission!(:view_wiki_edits) if r.has_permission?(:view_wiki_pages)
  	end
  end

  def self.down
	Role.find(:all).each do |r|
	  r.remove_permission!(:view_wiki_edits)
  	end
  end
end