add import checksum

app/services/proforma_service/convert_task_to_exercise.rb

@@ -22,7 +22,8 @@ module ProformaService
         description: @task.description,
         instructions: @task.internal_description,
         files: files,
-        uuid: @task.uuid
+        uuid: @task.uuid,
+        import_checksum: @task.checksum
       )
     end
 

db/migrate/20190905152630_add_import_checksum_to_exercises.rb

@@ -0,0 +1,5 @@
+class AddImportChecksumToExercises < ActiveRecord::Migration[5.2]
+  def change
+    add_column :exercises, :import_checksum, :string
+  end
+end