read only association are not editable anymore.

README.md

@@ -1207,6 +1207,8 @@ You can edit related objects in filtering-multiselect by double-clicking on any
 If you set the :inverse_of option on your relations, RailsAdmin will automatically populate the inverse relationship
 in the modal creation window. (link next to belongs\_to and has\_many widgets)
 
+:readonly options are automatically inferred on associations fields and won't be editable in forms.
+
 ### Configuring fields ###
 
 * exclude_fields field_list

lib/rails_admin/adapters/active_record.rb

@@ -137,7 +137,8 @@ def associations
             :foreign_type => association_foreign_type_lookup(association),
             :as => association_as_lookup(association),
             :polymorphic => association_polymorphic_lookup(association),
-            :inverse_of => association_inverse_of_lookup(association)
+            :inverse_of => association_inverse_of_lookup(association),
+            :read_only => association_read_only_lookup(association)
           }
         end
       end
@@ -209,6 +210,10 @@ def association_parent_key_lookup(association)
       def association_inverse_of_lookup(association)
         association.options[:inverse_of].try :to_sym
       end
+
+      def association_read_only_lookup(association)
+        association.options[:readonly]
+      end
 
       def association_child_model_lookup(association)
         case association.macro

lib/rails_admin/config/fields.rb

@@ -10,7 +10,11 @@ module Fields
         # If it's an association
         if properties.has_key?(:parent_model)
           association = parent.abstract_model.associations.find {|a| a[:name].to_s == properties[:name].to_s}
-          fields << RailsAdmin::Config::Fields::Types.load("#{association[:polymorphic] ? :polymorphic : properties[:type]}_association").new(parent, properties[:name], association)
+          field = RailsAdmin::Config::Fields::Types.load("#{association[:polymorphic] ? :polymorphic : properties[:type]}_association").new(parent, properties[:name], association)
+
+          field.read_only(true) if association[:read_only]
+          fields << field
+
         # If it's a column
         elsif !properties.has_key?(:parent_model)
           fields << (field = RailsAdmin::Config::Fields::Types.load(properties[:type]).new(parent, properties[:name], properties))

lib/rails_admin/config/fields/association.rb

@@ -79,7 +79,7 @@ def child_key
         def inverse_of
           association[:inverse_of]
         end
-
+        
         # Reader for validation errors of the bound object
         def errors
           bindings[:object].errors[child_key]

spec/dummy_app/app/models/league.rb

@@ -2,7 +2,7 @@ class League < ActiveRecord::Base
   validates_presence_of(:name)
 
   has_many :divisions
-  has_many :teams, :through => :divisions
+  has_many :teams, :through => :divisions, :readonly => true
 
   def custom_name
     "League '#{self.name}'"

spec/requests/basic/edit/rails_admin_basic_edit_spec.rb

@@ -39,7 +39,17 @@
       should have_selector("a", :href => 'admin/players/new?associations[team]=' + @team.id.to_s)
     end
   end
-
+
+  describe "readonly associations" do
+
+    it 'should not be editable' do
+      @league = FactoryGirl.create :league
+      visit rails_admin_edit_path(:model_name => "league", :id => @league.id)
+      should_not have_selector('select#league_team_ids')
+      should have_selector('select#league_division_ids') # decoy, fails if naming scheme changes
+    end
+  end
+
   describe "edit with has-one association" do
     before(:each) do
       @player = FactoryGirl.create :player