Add CostObject and VariableCostObject journals (model and migrations), extend WorkPackageJournal.

app/models/cost_object.rb

@@ -17,6 +17,7 @@ class CostObject < ActiveRecord::Base
   unless respond_to? :acts_as_journalized
     acts_as_event :title => Proc.new {|o| "#{l(:label_cost_object)} ##{o.id}: #{o.subject}"},
                   :url => Proc.new {|o| {:controller => '/cost_objects', :action => 'show', :id => o.id}}
+  acts_as_journalized
 
     acts_as_activity_provider :find_options => {:include => [:project, :author]},
                               :timestamp => "#{table_name}.updated_on",

app/models/journal/cost_object_journal.rb

@@ -0,0 +1,43 @@
+#-- encoding: UTF-8
+#-- copyright
+# OpenProject is a project management system.
+#
+# Copyright (C) 2012-2013 the OpenProject Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version 3.
+#
+# See doc/COPYRIGHT.rdoc for more details.
+#++
+
+class Journal::CostObjectJournal < ActiveRecord::Base
+
+  # include ActiveModel::ForbiddenAttributesProtection
+
+  self.table_name = "cost_object_journals"
+
+  belongs_to :journal
+
+  # attr_accessible :project_id, :author_id, :subject, :description, :fixed_date, :created_on
+
+  # acts_as_journalized
+
+  # acts_as_journalized :event_type => 'cost-object',
+  #   :event_title => Proc.new {|o| "#{l(:label_cost_object)} ##{o.journaled.id}: #{o.subject}"},
+  #   :event_url => Proc.new {|o| {:controller => 'cost_objects', :action => 'show', :id => o.journaled.id}},
+  #   :activity_type => superclass.plural_name,
+  #   :activity_find_options => {:include => [:project, :author]},
+  #   :activity_timestamp => "#{table_name}.updated_on",
+  #   :activity_author_key => :author_id,
+  #   :activity_permission => :view_cost_objects
+
+  @@journaled_attributes = [:project_id,
+                            :author_id,
+                            :subject,
+                            :description,
+                            :fixed_date]
+
+  def journaled_attributes
+    attributes.symbolize_keys.select{|k,_| @@journaled_attributes.include? k}
+  end
+end

app/models/journal/variable_cost_object_journal.rb

@@ -0,0 +1,34 @@
+
+#-- encoding: UTF-8
+#-- copyright
+# OpenProject is a project management system.
+#
+# Copyright (C) 2012-2013 the OpenProject Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version 3.
+#
+# See doc/COPYRIGHT.rdoc for more details.
+#++
+
+class Journal::VariableCostObjectJournal < Journal::CostObjectJournal
+
+  # include ActiveModel::ForbiddenAttributesProtection
+
+  # self.table_name = "cost_object_journals"
+
+  # belongs_to :journal
+
+  # attr_accessible :type, :id, :project_id, :author_id, :subject, :description, :fixed_date, :created_on
+
+  # @@journaled_attributes = [:project_id,
+  #                           :author_id,
+  #                           :subject,
+  #                           :description,
+  #                           :type,
+  #                           :fixed_date]
+
+  # def journaled_attributes
+  #   attributes.symbolize_keys.select{|k,_| @@journaled_attributes.include? k}
+  # end
+end

db/migrate/20130918084158_add_cost_object_journals.rb

@@ -0,0 +1,40 @@
+#-- copyright
+# OpenProject is a project management system.
+# Copyright (C) 2012-2013 the OpenProject Foundation (OPF)
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version 3.
+#
+# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
+# Copyright (C) 2006-2013 Jean-Philippe Lang
+# Copyright (C) 2010-2013 the ChiliProject Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+# See doc/COPYRIGHT.rdoc for more details.
+#++
+class AddCostObjectJournals < ActiveRecord::Migration
+  def change
+    create_table :cost_object_journals do |t|
+      t.integer  :journal_id,  :null => false
+      t.integer  :project_id,  :null => false
+      t.integer  :author_id,   :null => false
+      t.string   :subject,     :null => false
+      t.text     :description, :null => false
+      t.date     :fixed_date,  :null => false
+      t.datetime :created_on
+    end
+  end
+end

db/migrate/20130918084919_add_cost_object_id_to_work_package_journals.rb

@@ -0,0 +1,5 @@
+class AddCostObjectIdToWorkPackageJournals < ActiveRecord::Migration
+  def change
+    add_column :work_package_journals, :cost_object_id, :integer, null: true
+  end
+end