add data migration to localize files with external URLs

sdbs_pile/pile/migrations/0008_localize_files_20200401_1221.py

@@ -0,0 +1,23 @@
+# Generated by Django 3.0.4 on 2020-04-01 10:21
+from urllib.parse import unquote
+
+from django.db import migrations
+
+
+# noinspection PyPep8Naming
+def localize_file(apps, schema_editor):
+    Document = apps.get_model('pile', 'Document')
+    for document in Document.objects.all():
+        if not bool(document.file) and "pile.sdbs.cz" in document.external_url:
+            document.file.name = unquote(document.external_url.split("/")[-1])
+            document.save()
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('pile', '0007_document_status'),
+    ]
+
+    operations = [
+        migrations.RunPython(localize_file)
+    ]