the main distribution is now 20.04

rainboard/migrations/0064_main_focal.py

+# Generated by Django 3.2.7 on 2021-09-14 12:07
+
+from django.db import migrations
+
+
+def main_focal(apps, schema_editor):
+    Target = apps.get_model('rainboard', 'Target')
+    Target.objects.filter(name='18.04').update(main=False)
+    Target.objects.filter(name='20.04').update(main=True)
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('rainboard', '0063_alter_project_clang_format'),
+    ]
+
+    operations = [
+        migrations.RunPython(main_focal),
+    ]