Add documentation and source

Added documentation, source and extra files.

source/orm/library/migrations/0002_add_book_year.py

@@ -0,0 +1,24 @@
+# Generated by Django 3.2 on 2021-04-12 14:58
+
+from django.db import migrations, models
+import library.models.book
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('library', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='book',
+            name='year',
+            field=models.PositiveIntegerField(db_index=True, default=1950, null=True, verbose_name='published'),
+        ),
+        migrations.AlterField(
+            model_name='book',
+            name='isbn',
+            field=models.CharField(default=library.models.book.generate_isbn, max_length=64, verbose_name='ISBN'),
+        ),
+    ]