render custom_fields in rabl views

eagerly load custom field translations

app/controllers/api/v2/planning_elements_controller.rb

@@ -80,7 +80,8 @@ module Api
       end
 
       def show
-        @planning_element = @project.work_packages.find(params[:id])
+        @planning_element = @project.work_packages.find params[:id],
+          :include => [{:custom_values => [{:custom_field => :translations}]}]
 
         respond_to do |format|
           format.api

app/controllers/api/v2/projects_controller.rb

@@ -80,7 +80,8 @@ module Api
       protected
 
       def find_project
-        @project = Project.find(params[:id])
+        @project = Project.find params[:id],
+          :include => [{:custom_values => [{:custom_field => :translations}]}]
       end
 
       def build_associations

app/views/api/v2/planning_elements/_planning_element.api.rabl

@@ -75,6 +75,9 @@ node :assigned_to, if: lambda{|pe| pe.assigned_to.present?} do |pe|
   end
 end
 
+node :custom_fields do
+  partial "api/v2/custom_fields/values", :object => (locals[:object] || @planning_element).custom_values
+end
 
 node :journals, if: lambda{|pe| include_journals?} do |pe|
   pe.journals.map do |journal|

app/views/api/v2/projects/_project.api.rabl

@@ -82,3 +82,6 @@ node :parent, if: lambda{|project| visible_parent_project(project).present?} do
   { id: parent.id, name: parent.name, identifier: parent.identifier }
 end
 
+node :custom_fields do
+  partial "api/v2/custom_fields/values", :object => (locals[:object] || @project).custom_values
+end