Fix template bug.

backend/src/Squidex.Domain.Apps.Entities/Apps/Templates/TemplateCommandMiddleware.cs

@@ -47,14 +47,19 @@ namespace Squidex.Domain.Apps.Entities.Apps.Templates
         {
             await next(context);
 
-            if (context.IsCompleted && context.Command is CreateApp createApp && !string.IsNullOrWhiteSpace(createApp.Template))
+            if (context.IsCompleted && context.Command is CreateApp createApp)
             {
                 await ApplyTemplateAsync(context.Result<IAppEntity>(), createApp.Template);
             }
         }
 
-        private async Task ApplyTemplateAsync(IAppEntity app, string template)
+        private async Task ApplyTemplateAsync(IAppEntity app, string? template)
         {
+            if (string.IsNullOrWhiteSpace(template))
+            {
+                return;
+            }
+
             var repository = await templatesClient.GetRepositoryUrl(template);
 
             if (string.IsNullOrEmpty(repository))

backend/src/Squidex/Areas/Api/Controllers/Apps/Models/CreateAppDto.cs

@@ -20,6 +20,11 @@ namespace Squidex.Areas.Api.Controllers.Apps.Models
         [LocalizedRegularExpression("^[a-z0-9]+(\\-[a-z0-9]+)*$")]
         public string Name { get; set; }
 
+        /// <summary>
+        /// Initialize the app with the inbuilt template.
+        /// </summary>
+        public string? Template { get; set; }
+
         public CreateApp ToCommand()
         {
             return SimpleMapper.Map(this, new CreateApp());