Add lot to stock model.

shimatta_kenkyusho/parts/migrations/0007_stock_lot.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.2.5 on 2021-12-30 22:32
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('parts', '0006_auto_20211114_1524'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='stock',
+            name='lot',
+            field=models.CharField(blank=True, max_length=255, null=True),
+        ),
+    ]

shimatta_kenkyusho/parts/models.py

@@ -227,6 +227,7 @@ class Stock(models.Model):
 	storage = models.ForeignKey(Storage, on_delete=models.PROTECT, blank=True, null=True)
 	amount = models.PositiveIntegerField()
 	watermark = models.IntegerField()  # negative is no watermark
+	lot = models.CharField(max_length=255, null=True, blank=True)
 
 	def atomic_increment(self, increment):
 		if self.amount + increment < 0: