Fixed all relationship and write errors in all entities

PyroFetes/Models/ProductEffect.cs

@@ -9,7 +9,7 @@ public class ProductEffect
     [Required] public Product? Product { get; set; }
     [Required] public int ProductId { get; set; }
 
-    [Required] public Effect? Effect { get; set; }
+    public Effect? Effect { get; set; }
     [Required] public int EffectId { get; set; }
 
 }