Add billable/non_billable methods to Project (from redmine_contracts)

init.rb

@@ -23,6 +23,8 @@ Dispatcher.to_prepare do
   require_dependency 'enumeration'
   require_dependency 'time_entry_activity'
   TimeEntryActivity.send(:include, OverheadTimeEntryActivityPatch)
+  require_dependency 'project'
+  Project.send(:include, RedmineOverhead::Patches::ProjectPatch)
 end
 
 require 'overhead_budget_hook'

lib/redmine_overhead/patches/project_patch.rb

@@ -0,0 +1,41 @@
+module RedmineOverhead
+  module Patches
+    module ProjectPatch
+      def self.included(base)
+        base.extend(ClassMethods)
+
+        base.send(:include, InstanceMethods)
+        base.class_eval do
+          unloadable
+        end
+      end
+
+      module ClassMethods
+      end
+
+      module InstanceMethods
+        def billable_activities
+          activities_sorted_by_billable[:billable]
+        end
+
+        def non_billable_activities
+          activities_sorted_by_billable[:non_billable]
+        end
+
+        private
+
+        def activities_sorted_by_billable
+          split_activities = activities.partition do |activity|
+            activity.billable?
+          end
+
+          {
+            :billable => split_activities.first,
+            :non_billable => split_activities.second
+          }
+
+        end
+      end
+    end
+  end
+end