Add a custom manager to filter private and unpublished stuff (#39)

* Implement a customer manager for flatpages

* Implement public manager for private objects

* Add support for unpublished objects in roster and consist

* Add support for unpublished objects in bookshelf

* Update filtering on REST views

* Use uuid in urls.py

* Increment version

ram/roster/admin.py

@@ -111,6 +111,7 @@ class RollingStockAdmin(SortableAdminBase, admin.ModelAdmin):
     readonly_fields = ("preview", "creation_time", "updated_time")
     list_display = (
         "__str__",
+        "published",
         "address",
         "manufacturer",
         "scale",
@@ -141,6 +142,7 @@ class RollingStockAdmin(SortableAdminBase, admin.ModelAdmin):
             {
                 "fields": (
                     "preview",
+                    "published",
                     "rolling_class",
                     "road_number",
                     "scale",