refactoring class methods for scopes concepts and add import topics task

app/controllers/learning_objects_controller.rb

@@ -4,7 +4,6 @@ class LearningObjectsController < ApplicationController
   include Reportable
 
   before_action :authenticate_user!, except: [:index, :show]
-
   before_action :set_learning_object, only: [:show, :edit, :update,
                                              :destroy, :like, :bookmarks,
                                              :collections, :upload, :upload_link, :download]
@@ -21,7 +20,7 @@ class LearningObjectsController < ApplicationController
   def new
     @learning_object = LearningObject.new
     @school_levels = ['Educação Infantil', 'Ensino Fundamental', 'Ensino Médio']
-    @subjects = Topic.all.map{|x| x.name}.uniq
+    @subjects = Topic.defaults
     @types = LearningObject.default_types
     @languages = Language.all
   end

app/models/topic.rb

@@ -10,10 +10,5 @@ class Topic < ActiveRecord::Base
   validates_presence_of :name
   validates_uniqueness_of :name
 
-  def self.default_list
-    ['Artes', 'Biologia', 'Ciências', 'Educação Física', 'Filosofia',
-     'Física', 'Geografia', 'História', 'Matemática', 'Língua Portuguesa', 'Química', 'Sociologia'].map do |topic|
-      Topic.find_by_name(topic)
-    end
-  end
+  scope :defaults, -> { where(default: true) }
 end

db/migrate/20160217122253_create_default_column_for_topics.rb

+class CreateDefaultColumnForTopics < ActiveRecord::Migration
+  def change
+    add_column :topics, :default, :boolean, default: false
+  end
+end

lib/tasks/topics.rake

+namespace :topics do
+
+  desc "Define defaults topics"
+  task :define_defaults => :environment do
+    ['Artes', 'Biologia', 'Ciências', 'Educação Física', 'Filosofia',
+     'Física', 'Geografia', 'História', 'Matemática', 'Língua Portuguesa', 'Química', 'Sociologia'].map do |name|
+      t = Topic.find_by_name(name)
+      if t.class == Topic
+        t.default = true
+        t.save
+      end
+    end
+  end
+
+end