create highlights method for LearningObject

app/models/learning_object.rb

@@ -131,4 +131,19 @@ class LearningObject < ActiveRecord::Base
   def user_category
     publisher.try('user_category')
   end
+
+  #period is either :week or :month
+  def self.highlights(period, limit)
+    if period == :week
+      los = LearningObject.this_week
+    elsif period == :month
+      los = LearningObject.this_month
+    else
+      los = LearningObject.all
+    end
+
+    los.order(score: :desc)
+    highlights = los.first(limit)
+    return highlights
+  end
 end