first commit

core/apps/management/models/district.py

@@ -0,0 +1,16 @@
+from django.db import models
+from .region import Region
+
+class District(models.Model):
+    region = models.ForeignKey(
+        Region,
+        on_delete=models.CASCADE,
+        related_name="districts"
+    )
+    name = models.CharField(max_length=100)
+
+    class Meta:
+        unique_together = ("region", "name")
+
+    def __str__(self):
+        return f"{self.name} — {self.region.name}"