Done

app/Models/Category.php

@@ -0,0 +1,40 @@
+<?php
+
+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
+{
+    use HasFactory;
+
+    protected $fillable = [
+        'user_id',
+        'parent_id',
+        'title',
+        'description',
+    ];
+
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+
+    public function parent(): BelongsTo
+    {
+        return $this->belongsTo(Category::class, 'parent_id');
+    }
+
+    public function children(): HasMany
+    {
+        return $this->hasMany(Category::class, 'parent_id');
+    }
+
+    public function feeds(): HasMany
+    {
+        return $this->hasMany(Feed::class);
+    }
+}