env Variables & README.md updates

.env.example

@@ -1,6 +1,6 @@
 ###################
 # OPENAI CHATGPT  #
 ###################
-MRX_OPEN_AI_API_KEY=
+OPENAI_API_KEY=
 # Default: gpt-3.5-turbo
-MRX_OPEN_AI_DEFAULT_MODEL=
+OPENAI_DEFAULT_MODEL=

README.md

@@ -23,15 +23,21 @@ php artisan vendor:publish --provider="Marxolity\OpenAi\Providers\OpenAIServiceP
 ```
 Set up your environment variables:
 ```bash
-MRX_OPEN_AI_API_KEY="<<YOUR_API_KEY>>"
+OPENAI_API_KEY="<<YOUR_API_KEY>>"
 ```
 ---
 ## Usage
 ```php
    use \Marxolity\OpenAi\Facades\OpenAi;
 ```
-Retrieve Response Message
+Changing Model then Retrieve responseMessage (Ex: Change model to `gpt-4`)
+```php
+   $responseMessage = OpenAi::query("What is Laravel?")
+        ->setModel('gpt-4')
+        ->send()->responseMessage;
+```
 
+Retrieve Response Message
 ```php
    $responseMessage = OpenAi::query("What is Laravel?")->send()->responseMessage;
 ```

src/config/ai.php

@@ -2,7 +2,7 @@
 
 return [
     'open_ai' => [
-        'api_key' => env('MRX_OPEN_AI_API_KEY'),
-        'default_model' => env('MRX_OPEN_AI_DEFAULT_MODEL', 'gpt-3.5-turbo'),
+        'api_key' => env('OPENAI_API_KEY'),
+        'default_model' => env('OPENAI_DEFAULT_MODEL', 'gpt-3.5-turbo'),
     ],
 ];