feat: add all Eloquent models with relationships

app/Models/CashCategory.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+
+class CashCategory extends Model
+{
+    protected $fillable = ['name'];
+
+    public function records(): HasMany
+    {
+        return $this->hasMany(CashRecord::class, 'category_id');
+    }
+}