Add migration.

biscuit/apps/chronos/migrations/0001_initial.py

+# Generated by Django 2.2.3 on 2019-07-16 11:42
+
+import django.core.validators
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+        ('core', '0004_group'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Subject',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('abbrev', models.CharField(max_length=10, verbose_name='Abbreviation of subject in timetable')),
+                ('name', models.CharField(max_length=30, verbose_name='Long name of subject')),
+                ('colour_fg', models.CharField(blank=True, max_length=7, validators=[django.core.validators.RegexValidator('#[0-9A-F]{6}')], verbose_name='Foreground colour in timetable')),
+                ('colour_bg', models.CharField(blank=True, max_length=7, validators=[django.core.validators.RegexValidator('#[0-9A-F]{6}')], verbose_name='Background colour in timetable')),
+            ],
+        ),
+        migrations.CreateModel(
+            name='TimePeriod',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('weekday', models.PositiveSmallIntegerField(choices=[(0, 'Sunday'), (1, 'Monday'), (2, 'Tuesday'), (3, 'Wednesday'), (4, 'Thursday'), (5, 'Friday'), (6, 'Saturday')], verbose_name='Week day')),
+                ('period', models.PositiveSmallIntegerField(verbose_name='Number of period')),
+                ('time_start', models.TimeField(verbose_name='Time the period starts')),
+                ('time_end', models.TimeField(verbose_name='Time the period ends')),
+            ],
+        ),
+        migrations.CreateModel(
+            name='Lesson',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('date_start', models.DateField(null=True, verbose_name='Effective start date of lesson')),
+                ('date_end', models.DateField(null=True, verbose_name='Effective end date of lesson')),
+                ('groups', models.ManyToManyField(related_name='lessons', to='core.Group')),
+                ('periods', models.ManyToManyField(related_name='lessons', to='chronos.TimePeriod')),
+                ('subject', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='lessons', to='chronos.Subject')),
+                ('teachers', models.ManyToManyField(related_name='lessons', to='core.Person')),
+            ],
+        ),
+    ]