Refactor rolling stock

dcc/metadata/admin.py

@@ -1,5 +1,6 @@
 from django.contrib import admin
-from metadata.models import Decoder, Manufacturer, Company, Tag
+from metadata.models import (
+    Decoder, Manufacturer, Company, Tag, RollingStockType)
 
 
 @admin.register(Decoder)
@@ -20,3 +21,9 @@ class ManufacturerAdmin(admin.ModelAdmin):
 @admin.register(Tag)
 class TagAdmin(admin.ModelAdmin):
     readonly_fields = ('slug',)
+
+
+@admin.register(RollingStockType)
+class RollingStockTypeAdmin(admin.ModelAdmin):
+    list_display = ('type', 'category')
+    list_filter = list_display