fix: reconfigure currency exchange rate feature

README.md

 
     php artisan migrate:refresh
 
+## Currency Exchange Rates
+
+### Overview
+
+This application offers support for real-time currency exchange rates. This feature is disabled by default. To enable it, you must first register for an API key at [ExchangeRate-API](https://www.exchangerate-api.com/). The application uses this service due to its generous provision of up to 1,500 free API calls per month, which should be enough for development and testing purposes.
+
+**Disclaimer**: There is no affiliation between this application and ExchangeRate-API.
+
+Once you have your API key, you can enable the feature by setting the `CURRENCY_API_KEY` environment variable in your `.env` file.
+
+### Configuration
+
+Of course, you may use any service you wish to retrieve currency exchange rates. If you decide to use a different service, you can update the `config/services.php` file with your choice:
+
+```php
+'currency_api' => [
+    'key' => env('CURRENCY_API_KEY'),
+    'base_url' => 'https://v6.exchangerate-api.com/v6',
+],
+```
+
+Additionally, you may update the following method in the `app/Services/CurrencyService.php` file which is responsible for retrieving the exchange rate:
+
+```php
+public function getExchangeRate($from, $to)
+{
+    $api_key = config('services.currency_api.key');
+    $base_url = config('services.currency_api.base_url');
+
+    $req_url = "{$base_url}/{$api_key}/pair/{$from}/{$to}";
+
+    $response = Http::get($req_url);
+
+    if ($response->successful()) {
+        $responseData = $response->json();
+        if (isset($responseData['conversion_rate'])) {
+            return $responseData['conversion_rate'];
+        }
+    }
+
+    return null;
+}
+```
+
+### Important Information
+
+- To use the currency exchange rate feature, you must first obtain an API key from a service provider. This application is configured to use a service that offers a free tier suitable for development and testing purposes.
+- Your API key is sensitive information and should be kept secret. Do not commit it to your repository or share it with anyone.
+- Note that API rate limits may apply depending on the service you choose. Make sure to review the terms for your chosen service.
+
 ## Dependencies
 
 - [filamentphp/filament](https://github.com/filamentphp/filament) - A collection of beautiful full-stack components

app/Services/CurrencyService.php

 {
     public function getExchangeRate($from, $to)
     {
-        $req_url = 'https://api.exchangerate.host/latest?base=' . $from . '&symbols=' . $to;
+        $api_key = config('services.currency_api.key');
+        $base_url = config('services.currency_api.base_url');
+
+        $req_url = "{$base_url}/{$api_key}/pair/{$from}/{$to}";
 
         $response = Http::get($req_url);
 
         if ($response->successful()) {
             $responseData = $response->json();
-            if (isset($responseData['rates'][$to])) {
-                return $responseData['rates'][$to];
+            if (isset($responseData['conversion_rate'])) {
+                return $responseData['conversion_rate'];
             }
         }
 

config/services.php

         'redirect' => 'http://erpsaas.test/company/oauth/github/callback',
     ],
 
+    'currency_api' => [
+        'key' => env('CURRENCY_API_KEY'),
+        'base_url' => 'https://v6.exchangerate-api.com/v6',
+    ],
+
 ];