add category views for each type of ride, add ride designers

designers/admin.py

@@ -0,0 +1,10 @@
+from django.contrib import admin
+from simple_history.admin import SimpleHistoryAdmin
+from .models import Designer
+
+@admin.register(Designer)
+class DesignerAdmin(SimpleHistoryAdmin):
+    list_display = ('name', 'headquarters', 'founded_date', 'website')
+    search_fields = ('name', 'headquarters')
+    list_filter = ('founded_date',)
+    prepopulated_fields = {'slug': ('name',)}