add null=True to vimeo_id field so db allows NULLable, add migration

app/video/migrations/0004_alter_film_vimeo_id.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.2.7 on 2021-10-23 09:46
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('video', '0003_film_position'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='film',
+            name='vimeo_id',
+            field=models.CharField(blank=True, null=True, default=None, max_length=255),
+        ),
+    ]