feat(home/models.py): add CoursePage page with group restriction

home/models.py

@@ -2,9 +2,39 @@ from django.db import models
 
 from wagtail.models import Page
 from wagtail.fields import RichTextField
+from django.contrib.auth.models import Group
 
 
 class HomePage(Page):
     body = RichTextField(blank=True)
 
     content_panels = Page.content_panels + ["body"]
+
+
+class CoursePage(Page):
+    body = RichTextField(blank=True)
+    group = models.ForeignKey(
+        Group,
+        on_delete=models.CASCADE,
+        null=True,
+        blank=True,
+        help_text="Only members of this group can access this course.",
+    )
+
+    content_panels = Page.content_panels + [
+        "body",
+        "group",
+    ]
+
+    def serve(self, request):
+        if self.group:
+            if (
+                not request.user.is_authenticated
+                or self.group not in request.user.groups.all()
+            ):
+                from django.shortcuts import render
+
+                # render 403.html
+                return render(request, "403.html", status=403)
+
+        return super().serve(request)