fixed ActiveRecord::ReadOnlyRecord error raised when using resources …

…instances returned by Resource.with_role method

using .select in resource_adapter to prevent Rails to flag the association as read-only
added specs to cover this use case
closes #175

lib/rolify/adapters/active_record/resource_adapter.rb

@@ -7,6 +7,7 @@ def resources_find(roles_table, relation, role_name)
         resources = relation.joins("INNER JOIN #{quote(roles_table)} ON #{quote(roles_table)}.resource_type = '#{relation.to_s}' AND
                                     (#{quote(roles_table)}.resource_id IS NULL OR #{quote(roles_table)}.resource_id = #{quote(relation.table_name)}.#{relation.primary_key})")
         resources = resources.where("#{quote(roles_table)}.name IN (?) AND #{quote(roles_table)}.resource_type = ?", Array(role_name), relation.to_s)
+        resources = resources.select("#{quote(relation.table_name)}.*")
         resources
       end
 

spec/rolify/resource_spec.rb

@@ -38,9 +38,16 @@
         it "should include Forum instances with forum role" do
           subject.with_role(:forum).should =~ [ Forum.first, Forum.last ]
         end
+
         it "should include Forum instances with godfather role" do
           subject.with_role(:godfather).should =~ Forum.all.to_a
         end
+
+        it "should be able to modify the resource", :if => ENV['ADAPTER'] == 'active_record' do
+          forum_resource = subject.with_role(:forum).first
+          forum_resource.name = "modified name"
+          expect(forum_resource.save).not_to raise_error
+        end
       end
 
       context "on the Group class" do