Merge branch 'download_statistics' into 'master'

Added download by month query to statistics controller

See merge request !387

app/controllers/v1/statistics_controller.rb

 class V1::StatisticsController < ApplicationController
-
+  # GET v1/statistics
+  # GET v1/statistics.json
   def index
-    statistics = {:count => count_learning_objects, :month_publications => month_publications, :month_downloads => month_downloads}
+    statistics = { count: count_learning_objects, month_publications: month_publications, month_downloads: month_downloads }
     render json: statistics
   end
 
   private
-    def count_learning_objects
-      LearningObject.where('state = ?', LearningObject.states[:published]).count
-    end
 
-    def month_publications
-      LearningObject.where('extract (month from published_at) = ? and extract (year from published_at) = ?', Time.now.month, Time.now.year).count
-    end
+  def count_learning_objects
+    LearningObject.where('state = ?', LearningObject.states[:published]).count
+  end
 
-    def month_downloads
-    end
+  def month_publications
+    LearningObject.where('extract (month from published_at) = ? and extract (year from published_at) = ?', Time.current.month, Time.current.year).count
+  end
+
+  def month_downloads
+    Download.where('extract (month from created_at) = ? and extract (year from created_at) = ?', Time.current.month, Time.current.year).count
+  end
 end