Added Item model, resource and its API.

Updated Category model to have Items.

app/Models/Category.php

@@ -5,6 +5,7 @@ namespace App\Models;
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
 
 class Category extends Model
 {
@@ -20,4 +21,9 @@ class Category extends Model
     {
         return $this->belongsTo(Company::class);
     }
+
+    public function items(): HasMany
+    {
+        return $this->hasMany(Item::class);
+    }
 }