Added the ability to archive projects:

* Only administrators can archive/unarchive projects.
* Once archived, the project is visible on the admin project listing only. It doesn't show up anywhere else in the app. Subprojects are also archived.
* Archive/unarchive preserve everything on the project (issues, members, ...).
* A subproject can not be unarchived if its parent project is archived.

git-svn-id: http://redmine.rubyforge.org/svn/trunk@549 e93f8b46-1217-0410-a6f0-8f06a7374b81

db/migrate/051_add_project_status.rb

@@ -0,0 +1,9 @@
+class AddProjectStatus < ActiveRecord::Migration
+  def self.up
+    add_column :projects, :status, :integer, :default => 1, :null => false
+  end
+
+  def self.down
+    remove_column :projects, :status
+  end
+end