Add DropDownList migration task

lib/tasks/deployment/20200618121241_drop_down_list_options_to_json.rake

@@ -0,0 +1,25 @@
+namespace :after_party do
+  desc 'Deployment task: drop_down_list_options_to_json'
+  task drop_down_list_options_to_json: :environment do
+    puts "Running deploy task 'drop_down_list_options_to_json'"
+
+    types_de_champ = TypeDeChamp.joins(:drop_down_list).where(type_champ: [
+      TypeDeChamp.type_champs.fetch(:drop_down_list),
+      TypeDeChamp.type_champs.fetch(:multiple_drop_down_list),
+      TypeDeChamp.type_champs.fetch(:linked_drop_down_list)
+    ])
+    progress = ProgressReport.new(types_de_champ.count)
+    types_de_champ.find_each do |type_de_champ|
+      type_de_champ.drop_down_list_value = type_de_champ.drop_down_list_value
+      if type_de_champ.save
+        type_de_champ.drop_down_list.destroy
+      end
+      progress.inc
+    end
+    progress.finish
+
+    # Update task as completed.  If you remove the line below, the task will
+    # run with every deploy (or every time you call after_party:run).
+    AfterParty::TaskRecord.create version: '20200618121241'
+  end
+end