Fix: buildings can't be created in the admin UI (#445)

* Fix: buildings can't be created in the admin UI

* Makemigrations

* Formatting

src/meshapi/migrations/0012_alter_building_nodes.py

@@ -0,0 +1,26 @@
+# Generated by Django 4.2.13 on 2024-08-01 22:36
+
+from django.db import migrations
+
+import meshapi.models.util.custom_many_to_many
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("meshapi", "0011_los"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="building",
+            name="nodes",
+            field=meshapi.models.util.custom_many_to_many.CustomColumnNameManyToManyField(
+                blank=True,
+                db_from_column_name="building_id",
+                db_to_column_name="network_number",
+                help_text="All nodes located on the same structure (i.e. a discrete man-made place identified by the same BIN) that this Building is located within.",
+                related_name="buildings",
+                to="meshapi.node",
+            ),
+        ),
+    ]

src/meshapi/models/building.py

@@ -96,6 +96,7 @@ class Building(models.Model):
         help_text="All nodes located on the same structure (i.e. a discrete man-made place identified by the same BIN) "
         "that this Building is located within.",
         related_name="buildings",
+        blank=True,
     )
 
     def save(self, *args: Any, **kwargs: Any) -> None: