fixed issue

FoodHealthChecker/Program.cs

@@ -18,6 +18,7 @@ namespace FoodHealthChecker
                 return new MarkdownPipelineBuilder().UseSoftlineBreakAsHardlineBreak().Build();
             });
             builder.Services.AddAntiforgery(o => o.SuppressXFrameOptionsHeader = true);
+            builder.Services.AddSingleton<FoodCheckerPlugin>();
             builder.Services.AddSingleton<FoodCheckerService>();
 
             var app = builder.Build();