public function index()
{
   return ProductResource::collection(Product::with('inventories')->paginate(25));

}

class Product extends Model

public function inventories(){

    return $this->belongsToMany('AppInventory','inventory_product')->withPivot('price','stock')->withTimestamps();

}

class Inventory extends Model

public function products(){

    return $this->belongsToMany('AppProduct','inventory_product')->withPivot('price','stock')->withTimestamps();

 }

public function toArray($request)
{

   return [
       'id'=>$this->id,
       'name'=>$this->name,
       'description'=>$this->description,
       'short_description'=>$this->short_description,
       'category'=>$this->category,//category_id
       'url'=>$this->url,
       'image'=>$this->image,
       'relevant'=>$this->relevant,
       'month'=>$this->month,

       'price'=>$this->price,
       'stock'=>$this->stock
    ];
}

Schema::create('inventories', function (Blueprint $table) {
        $table->increments('id');
        $table->string('name');
        $table->unsignedInteger('city_id');
        $table->timestamps();

        $table-> foreign('city_id')->references('id')->on('cities')->onDelete('cascade');

    });

Schema::create('products', function (Blueprint $table) {
        $table->increments('id');
        $table ->string('name');
        //$table ->integer('stock');
        $table ->string('description');
        $table ->string('short_description');
        $table ->unsignedInteger('category');//category_id
        //$table ->integer('price');
        $table ->string('url');
        $table ->string('image');
        $table ->boolean('relevant');
        $table ->boolean('month');
        $table->timestamps();

        $table-> foreign('category')->references('id')->on('categories')->onDelete('cascade');

    });

$table->increments('id');
        $table->integer('inventory_id')->unsigned();
        $table->integer('product_id')->unsigned();
        $table ->integer('price');
        $table ->integer('stock');
        $table->timestamps();

        $table-> foreign('inventory_id')->references('id')->on('inventories')->onDelete('cascade');
        $table-> foreign('product_id')->references('id')->on('products')->onDelete('cascade');

{

{