如何在Laravel中附加多对多关系?

我的桌子是这样做的

产品表

Schema::create('products', function (Blueprint $table) {
            $table->increments('id');
            $table->timestamps();
            $table->string('image');
            $table->string('stock');
            $table->string('title');
            $table->string('slug')->unique();
            $table->string('gender');
            $table->text('description');
            $table->integer('price');
            $table->integer('user_id')->unsigned();
            $table->foreign('user_id')->references('id')->on('users')
                        ->onDelete('restrict')
                        ->onUpdate('restrict');

            $table->dateTime('published_at');
        });

和具有关系的颜色表

Schema::create('colors', function (Blueprint $table) {
            $table->increments('id');
            $table->string('name')->unique();
            $table->timestamps();
        });

        Schema::create('color_product', function (Blueprint $table) {
            $table->integer('color_id')->unsigned()->index();
            $table->foreign('color_id')->references('id')->on('colors')
                        ->onDelete('restrict')
                        ->onUpdate('restrict');
            $table->integer('product_id')->unsigned()->index();
            $table->foreign('product_id')->references('id')->on('products')
                        ->onDelete('restrict')
                        ->onUpdate('restrict');
            $table->timestamps();
        });

我正试图在这样的一款产品中添加更多颜色

public function addproductdetailspost(Request $request, $product){

        $product = product::where('slug', $product)->firstorfail();
        $color = color::where('name', $request->color)->firstOrCreate();
        $color->name = $request->color;
        $color->save();
        $product_id = $product->id;
        $color_id = $color->id;
        $product->colors()->attach($product_id);
        return Redirect::back()->with('status', 'Post Success');
    }

它不起作用,我收到了这个错误

Type error: Too few arguments to function Illuminate\Database\Eloquent\Builder::firstOrNew(), 0 passed in C:\xampp\htdocs\swimwear2\app\Http\Controllers\AdminController.php on line 109 and at least 1 expected