Adds a parent_readonly configuration option to has_many associations to

hide "Add another" buttons

app/views/rails_admin/main/_form_filtering_multiselect.html.haml

@@ -41,7 +41,7 @@
 
 - selected_ids = (hdv = field.html_default_value).nil? ? selected_ids : hdv
 = form.select field.method_name, collection, { :selected => selected_ids, :object => form.object }, field.html_attributes.reverse_merge({:data => { :filteringmultiselect => true, :options => js_data.to_json }, :multiple => true})
-- if authorized? :new, config.abstract_model
+- if authorized?(:new, config.abstract_model) && !field.parent_readonly
   - path_hash = { :model_name => config.abstract_model.to_param, :modal => true }
   - path_hash.merge!({ :associations => { field.inverse_of => (form.object.persisted? ? form.object.id : 'new') } }) if field.inverse_of
   = link_to "<i class=\"icon-plus icon-white\"></i> ".html_safe + wording_for(:link, :new, config.abstract_model), '#', :data => { :link => new_path(path_hash) }, :class => "create btn btn-info", :style => 'margin-left:10px'

lib/rails_admin/config/fields/types/has_many_association.rb

@@ -17,6 +17,11 @@ class HasManyAssociation < RailsAdmin::Config::Fields::Association
             false
           end
 
+          # read-only parent objects
+          register_instance_option :parent_readonly do
+            self.associated_model_config.excluded?
+          end
+
           def method_name
             nested_form ? "#{super}_attributes".to_sym : "#{super.to_s.singularize}_ids".to_sym  # name_ids
           end