Collections: add support for collection types.

We also added the field for invitations, as it's needed for collections
to work.

django_etebase/migrations/0031_auto_20201013_1336.py

@@ -0,0 +1,29 @@
+# Generated by Django 3.1.1 on 2020-10-13 13:36
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('django_etebase', '0030_auto_20200922_0832'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='CollectionType',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('uid', models.BinaryField(db_index=True, editable=True)),
+                ('owner', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL)),
+            ],
+        ),
+        migrations.AddField(
+            model_name='collectionmember',
+            name='collectionType',
+            field=models.ForeignKey(null=True, on_delete=django.db.models.deletion.PROTECT, to='django_etebase.collectiontype'),
+        ),
+    ]

django_etebase/migrations/0032_auto_20201013_1409.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.1.1 on 2020-10-13 14:09
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('django_etebase', '0031_auto_20201013_1336'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='collectiontype',
+            name='uid',
+            field=models.BinaryField(db_index=True, editable=True, unique=True),
+        ),
+    ]