Extend manufacturer and make volume frendly

dcc/metadata/admin.py

@@ -14,12 +14,14 @@ class DecoderAdmin(admin.ModelAdmin):
     readonly_fields = ("image_thumbnail",)
     list_display = ("__str__", "interface")
     list_filter = ("manufacturer", "interface")
+    search_fields = ("__str__",)
 
 
 @admin.register(Scale)
 class ScaleAdmin(admin.ModelAdmin):
     list_display = ("scale", "ratio", "gauge")
     list_filter = ("ratio", "gauge")
+    search_fields = list_display
 
 
 @admin.register(Company)
@@ -27,20 +29,26 @@ class CompanyAdmin(admin.ModelAdmin):
     readonly_fields = ("logo_thumbnail",)
     list_display = ("name", "country")
     list_filter = list_display
+    search_fields = ("name",)
 
 
 @admin.register(Manufacturer)
 class ManufacturerAdmin(admin.ModelAdmin):
     readonly_fields = ("logo_thumbnail",)
+    list_display = ("name", "category")
+    list_filter = ("category",)
+    search_fields = ("name",)
 
 
 @admin.register(Tag)
 class TagAdmin(admin.ModelAdmin):
     readonly_fields = ("slug",)
     list_display = ("name", "slug")
+    search_fields = ("name",)
 
 
 @admin.register(RollingStockType)
 class RollingStockTypeAdmin(admin.ModelAdmin):
     list_display = ("__str__",)
     list_filter = ("type", "category")
+    search_fields = list_display