feat: implement currency rates tracking with models, migrations and views

app/Models/Rate.php

@@ -0,0 +1,33 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+
+class Rate extends Model
+{
+    use HasFactory;
+
+    protected $fillable = [
+        'currency_id',
+        'city_id',
+        'buy_price',
+        'sell_price',
+        'date',
+    ];
+
+    protected $casts = [
+        'date' => 'date:Y-m-d',
+    ];
+
+    public function currency()
+    {
+        return $this->belongsTo(Currency::class);
+    }
+
+    public function city()
+    {
+        return $this->belongsTo(City::class);
+    }
+}