[scrobbles] Refactor run time sec to be blank by default

vrobbler/apps/beers/migrations/0006_remove_beer_run_time_seconds_and_more.py

@@ -0,0 +1,26 @@
+# Generated by Django 4.2.19 on 2025-10-30 01:52
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('beers', '0005_alter_beer_run_time_seconds'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='beer',
+            name='run_time_seconds',
+        ),
+        migrations.RemoveField(
+            model_name='beer',
+            name='run_time_ticks',
+        ),
+        migrations.AddField(
+            model_name='beer',
+            name='base_run_time_seconds',
+            field=models.IntegerField(blank=True, null=True),
+        ),
+    ]