feat: refactor PivotModel to extend Model and initialize attributes correctly

Author: 3m1n3nc3

src/Model.ts

@@ -627,9 +627,9 @@ export abstract class Model<
         this: new (attributes: Record<string, unknown>) => TModel,
         attributes: Record<string, unknown>
     ): TModel {
-        const model = new this(attributes)
-            ; (model as unknown as Model).syncOriginal()
-            ; (model as unknown as Model).syncChanges({})
+        const model = new this(attributes);
+        (model as unknown as Model).syncOriginal();
+        (model as unknown as Model).syncChanges({})
 
         return model
     }

src/PivotModel.ts

@@ -1,3 +1,5 @@
+import { Model } from './Model'
+
 /**
  * Base pivot class that all pivot models should extend. 
  * 
@@ -6,8 +8,8 @@
  * @author Legacy (3m1n3nc3)
  * @since 2.0.0-next.18
  */
-export class PivotModel {
-    constructor(attributes: Record<string, unknown> = {}) {
-        Object.assign(this, attributes)
+export class PivotModel extends Model {
+    constructor(protected readonly attributes: Record<string, unknown> = {}) {
+        super(attributes)
     }
 }