Versions can now be created with no date.

Versions with no date appear at the end of the roadmap, sorted by name.

git-svn-id: http://redmine.rubyforge.org/svn/trunk@536 e93f8b46-1217-0410-a6f0-8f06a7374b81

db/migrate/048_allow_null_version_effective_date.rb

@@ -0,0 +1,9 @@
+class AllowNullVersionEffectiveDate < ActiveRecord::Migration
+  def self.up
+    change_column :versions, :effective_date, :date, :default => nil
+  end
+
+  def self.down
+    raise IrreversibleMigration
+  end
+end