feat: improve admin and add demo data command

backend/checkins/admin.py

@@ -5,7 +5,14 @@ from .models import CheckIn
 
 @admin.register(CheckIn)
 class CheckInAdmin(admin.ModelAdmin):
-    list_display = ("reservation", "checked_in_at", "checked_in_by", "source", "created_at")
+    list_display = (
+        "reservation",
+        "performance",
+        "checked_in_at",
+        "checked_in_by",
+        "source",
+        "created_at",
+    )
     list_filter = ("source", "checked_in_at", "created_at")
     search_fields = (
         "reservation__name",
@@ -14,4 +21,10 @@ class CheckInAdmin(admin.ModelAdmin):
         "checked_in_by__username",
         "checked_in_by__email",
     )
-    readonly_fields = ("created_at", "updated_at")
+    readonly_fields = ("created_at", "updated_at", "checked_in_at")
+    list_select_related = ("reservation", "reservation__performance", "checked_in_by")
+    autocomplete_fields = ("reservation", "checked_in_by")
+
+    @admin.display(description="Performance")
+    def performance(self, obj):
+        return obj.reservation.performance