Be more specific about which model's ID property is missing in error …

…message (#626)

Sources/FluentKit/Model/AnyModel.swift

@@ -40,6 +40,6 @@ extension AnyModel {
                 return idChild
             }
         }
-        fatalError("id property must be declared using @ID or @CompositeID")
+        fatalError("id property for model \(Self.self) must be declared using @ID or @CompositeID")
     }
 }