Add requirements section to README.md

README.md

@@ -17,12 +17,17 @@
 
 This package provides the Database target for the [yiisoft/log](https://github.com/yiisoft/log) library.
 
+## Requirements
+
+- PHP 7.4 or higher.
+- `PDO` PHP extension.
+
 ## Installation
 
 The package could be installed with composer:
 
 ```
-composer require yiisoft/log-target-db
+composer require yiisoft/log-target-db --prefer-dist
 ```
 
 ## General usage
@@ -71,6 +76,8 @@ You need to set up a database connection and run this console command to create
 
 See [Yii guide to logging](https://github.com/yiisoft/docs/blob/master/guide/en/runtime/logging.md) for more info.
 
+## Testing
+
 ### Unit testing
 
 The package is tested with [PHPUnit](https://phpunit.de/). To run tests:

composer.json

@@ -21,6 +21,7 @@
     "minimum-stability": "dev",
     "prefer-stable": true,
     "require": {
+        "ext-pdo": "*",
         "php": "^7.4|^8.0",
         "yiisoft/db": "^3.0@dev",
         "yiisoft/log": "^1.0",