refactor: impacts #17, #21, and #6, making Category many-to-many

mdi/migrations/0038_auto_20200324_0329.py

@@ -0,0 +1,24 @@
+# Generated by Django 3.0.3 on 2020-03-24 03:29
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('mdi', '0037_auto_20200323_0409'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='organization',
+            name='categories',
+            field=models.ManyToManyField(blank=True, null=True, to='mdi.Category'),
+        ),
+        migrations.AlterField(
+            model_name='organization',
+            name='category',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='category_orig', to='mdi.Category'),
+        ),
+    ]

mdi/migrations/0039_auto_20200324_0331.py

@@ -0,0 +1,21 @@
+# Generated by Django 3.0.3 on 2020-03-24 03:31
+
+from django.db import models, migrations
+
+
+def forward(apps, schema_editor):
+    Organization = apps.get_model("mdi", "Organization")
+    for organization in Organization.objects.all():
+        if organization.category is not None:
+            organization.categories.add(organization.category)
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('mdi', '0038_auto_20200324_0329'),
+    ]
+
+    operations = [
+        migrations.RunPython(forward)
+]

mdi/migrations/0040_remove_organization_category.py

@@ -0,0 +1,17 @@
+# Generated by Django 3.0.3 on 2020-03-24 03:51
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('mdi', '0039_auto_20200324_0331'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='organization',
+            name='category',
+        ),
+    ]