register and sign in pages

backend/locations/models.py

@@ -0,0 +1,31 @@
+from django.db import models
+
+
+class Atoll(models.Model):
+    name = models.CharField(max_length=100, unique=True)
+    # Maldivian administrative code, e.g. "F" for Faafu.
+    code = models.CharField(max_length=8, blank=True)
+    is_active = models.BooleanField(default=True)
+
+    class Meta:
+        ordering = ["name"]
+
+    def __str__(self):
+        return self.name
+
+
+class Island(models.Model):
+    atoll = models.ForeignKey(Atoll, on_delete=models.PROTECT, related_name="islands")
+    name = models.CharField(max_length=100)
+    is_active = models.BooleanField(default=True)
+
+    class Meta:
+        ordering = ["name"]
+        constraints = [
+            models.UniqueConstraint(
+                fields=["atoll", "name"], name="unique_island_name_per_atoll"
+            )
+        ]
+
+    def __str__(self):
+        return f"{self.name}, {self.atoll.name}"