added demo iframe page

backend/tabby/app/urls.py

@@ -12,6 +12,7 @@ urlpatterns = [
 
     path('app-dist/<version>/<path:path>', views.AppDistView.as_view()),
     path('terminal', views.TerminalView.as_view()),
+    path('demo', views.DemoView.as_view()),
 
     path('', include(api.urlpatterns)),
 ]

backend/tabby/app/views.py

@@ -22,6 +22,13 @@ class TerminalView(APIView):
         return response
 
 
+class DemoView(APIView):
+    def get(self, request, format=None):
+        response = static.serve(request, 'demo.html', document_root=str(settings.STATIC_ROOT))
+        response['X-Frame-Options'] = 'ALLOW-FROM https://tabby.sh'
+        return response
+
+
 class AppDistView(APIView):
     def get(self, request, version=None, path=None, format=None):
         fs = fsspec.filesystem(urlparse(settings.APP_DIST_STORAGE).scheme)