Improvements and driver stub for serial comms

dcc/roster/migrations/0013_cab_company.py

@@ -0,0 +1,19 @@
+# Generated by Django 4.0 on 2021-12-16 21:27
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('roster', '0012_company'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='cab',
+            name='company',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, to='roster.company'),
+        ),
+    ]