change learning_objects_count to return only the published objects

app/serializers/user_serializer.rb

@@ -13,6 +13,10 @@ class UserSerializer < ActiveModel::Serializer
     object.email if (current_user != nil)&&(object.id == current_user.id || current_user.is_admin?)
   end
 
+  def learning_objects_count
+    object.learning_objects.where('state = ?', LearningObject.states[:published]).count
+  end
+
   attributes :id, :email, :provider, :name, :description, :education, :score, :cover, :role_ids, :institution_ids, :avatar, :likes_count, :followed, :complained, :follows_count, :learning_objects_count, :collections_count, :created_at, :updated_at
   has_many :subjects
 end