Resolve "list of subjects should contain columns dependent on the study"

Closes #184 (closed)

smash/web/migrations/0071_auto_20171130_1607.py

+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.7 on 2017-11-30 16:07
+from __future__ import unicode_literals
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+# noinspection PyUnusedLocal
+# noinspection PyPep8Naming
+def create_default_study(apps, schema_editor):
+    # We can't import the Study model directly as it may be a newer
+    # version than this migration expects. We use the historical version.
+    Study = apps.get_model("web", "Study")
+    study = Study.objects.create()
+    study.name = "New study"
+    study.save()
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('web', '0070_auto_20171128_1124'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Study',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=255, verbose_name=b'Name')),
+            ],
+        ),
+        migrations.AlterField(
+            model_name='studysubject',
+            name='subject',
+            field=models.ForeignKey(editable=False, on_delete=django.db.models.deletion.CASCADE, to='web.Subject',
+                                    verbose_name=b'Subject'),
+        ),
+        migrations.AddField(
+            model_name='studysubject',
+            name='study',
+            field=models.ForeignKey(editable=False, null=True, on_delete=django.db.models.deletion.CASCADE,
+                                    to='web.Study', verbose_name=b'Study'),
+        ),
+        migrations.RunPython(create_default_study),
+        migrations.AlterField(
+            model_name='studysubject',
+            name='study',
+            field=models.ForeignKey(default=1, editable=False, on_delete=django.db.models.deletion.CASCADE, to='web.Study', verbose_name=b'Study'),
+            preserve_default=False,
+        ),
+
+    ]