Add sorting, enforce foreign keys

ram/metadata/admin.py

@@ -1,4 +1,6 @@
 from django.contrib import admin
+from adminsortable2.admin import SortableAdminMixin
+
 from metadata.models import (
     Property,
     Decoder,
@@ -54,7 +56,7 @@ class TagAdmin(admin.ModelAdmin):
 
 
 @admin.register(RollingStockType)
-class RollingStockTypeAdmin(admin.ModelAdmin):
+class RollingStockTypeAdmin(SortableAdminMixin, admin.ModelAdmin):
     list_display = ("__str__",)
     list_filter = ("type", "category")
     search_fields = list_display

ram/metadata/migrations/0004_alter_rollingstocktype_options_and_more.py

@@ -0,0 +1,23 @@
+# Generated by Django 4.0.6 on 2022-07-14 14:46
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('metadata', '0003_property_private'),
+    ]
+
+    operations = [
+        migrations.AlterModelOptions(
+            name='rollingstocktype',
+            options={'ordering': ['order']},
+        ),
+        migrations.AddField(
+            model_name='rollingstocktype',
+            name='order',
+            field=models.PositiveSmallIntegerField(default=0),
+            preserve_default=False,
+        ),
+    ]

ram/metadata/models.py

@@ -108,12 +108,14 @@ def tag_pre_save(sender, instance, **kwargs):
 
 class RollingStockType(models.Model):
     type = models.CharField(max_length=64)
+    order = models.PositiveSmallIntegerField()
     category = models.CharField(
         max_length=64, choices=settings.ROLLING_STOCK_TYPES
     )
 
     class Meta(object):
         unique_together = ("category", "type")
+        ordering = ["order"]
 
     def __str__(self):
         return "{0} {1}".format(self.type, self.category)