Minor admin improvements and remove unique_together deprecated Meta

Also make rolling stock unique per consist

ram/consist/admin.py

@@ -9,7 +9,14 @@ class ConsistItemInline(SortableInlineAdminMixin, admin.TabularInline):
     min_num = 1
     extra = 0
     autocomplete_fields = ("rolling_stock",)
-    readonly_fields = ("preview", "published", "address", "type", "company", "era")
+    readonly_fields = (
+        "preview",
+        "published",
+        "address",
+        "type",
+        "company",
+        "era",
+    )
 
 
 @admin.register(Consist)
@@ -19,9 +26,9 @@ class ConsistAdmin(SortableAdminBase, admin.ModelAdmin):
         "creation_time",
         "updated_time",
     )
-    list_display = ("identifier", "published", "company", "era")
-    list_filter = list_display
-    search_fields = list_display
+    list_filter = ("company", "era", "published")
+    list_display = ("__str__",) + list_filter
+    search_fields = ("identifier",) + list_filter
     save_as = True
 
     fieldsets = (

ram/consist/migrations/0013_consistitem_one_stock_per_consist.py

@@ -0,0 +1,20 @@
+# Generated by Django 5.1.4 on 2025-01-08 21:50
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("consist", "0012_consist_published"),
+        ("roster", "0030_rollingstock_price"),
+    ]
+
+    operations = [
+        migrations.AddConstraint(
+            model_name="consistitem",
+            constraint=models.UniqueConstraint(
+                fields=("consist", "rolling_stock"), name="one_stock_per_consist"
+            ),
+        ),
+    ]

ram/consist/migrations/0014_alter_consistitem_order.py

@@ -0,0 +1,18 @@
+# Generated by Django 5.1.4 on 2025-01-08 22:22
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("consist", "0013_consistitem_one_stock_per_consist"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="consistitem",
+            name="order",
+            field=models.PositiveIntegerField(default=1000),
+        ),
+    ]

ram/consist/models.py

@@ -54,10 +54,20 @@ class ConsistItem(models.Model):
         Consist, on_delete=models.CASCADE, related_name="consist_item"
     )
     rolling_stock = models.ForeignKey(RollingStock, on_delete=models.CASCADE)
-    order = models.PositiveIntegerField(default=0, blank=False, null=False)
+    order = models.PositiveIntegerField(
+        default=1000,  # make sure it is always added at the end
+        blank=False,
+        null=False
+    )
 
-    class Meta(object):
+    class Meta:
         ordering = ["order"]
+        constraints = [
+            models.UniqueConstraint(
+                fields=["consist", "rolling_stock"],
+                name="one_stock_per_consist"
+            )
+        ]
 
     def __str__(self):
         return "{0}".format(self.rolling_stock)