Use best practice for adding this library as a dependency using Composer

Author: sebastianbergmann

README.md

@@ -2,11 +2,11 @@
 
 ## Installation
 
-To add File_Iterator as a local, per-project dependency to your project, simply add a dependency on `phpunit/php-file-iterator` to your project's `composer.json` file. Here is a minimal example of a `composer.json` file that just defines a dependency on File_Iterator 1.4:
+You can add this library as a local, per-project dependency to your project using [Composer](https://getcomposer.org/):
 
-    {
-        "require": {
-            "phpunit/php-file-iterator": "~1.4"
-        }
-    }
+    composer require phpunit/php-file-iterator
+
+If you only need this library during development, for instance to run your project's test suite, then you should add it as a development-time dependency:
+
+    composer require --dev phpunit/php-file-iterator