feat: make models

app/Models/Category.php

+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+
+class Category extends Model
+{
+    use HasFactory;
+
+    protected $fillable = [
+        'name'
+    ];
+}

app/Models/Product.php

+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+
+class Product extends Model
+{
+    use HasFactory;
+
+    protected $fillable = [
+        'name',
+        'retailer_id'
+    ];
+}

app/Models/Retailer.php

+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+
+class Retailer extends Model
+{
+    use HasFactory;
+
+    protected $fillable = [
+        'name'
+    ];
+}