add untracked IProduct

Bücherwurm.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>netcoreapp3.1</TargetFramework>
+    <DebugType>portable</DebugType>
   </PropertyGroup>
 
 </Project>

IProduct.cs

@@ -0,0 +1,13 @@
+namespace Bücherwurm
+{
+    public interface IProduct
+    {
+        int ProductId {get; set;}
+
+        string Category {get; set; }
+
+        string ImageLink { get; set;}
+
+        void OverwriteNullId(int id);
+    }
+}