doc: fix README.

Author: smeghead

README.md

@@ -1,6 +1,10 @@
 # php-vendor-creadits
+
 php-vendor-creadits creates CREDITS file from LICENSE files of dependencies
 
+
+php-vendor-creadits was created as a PHP Composer version of gocredits (https://github.com/Songmu/gocredits).
+
 ## Install
 
 ### From Composer
@@ -12,5 +16,5 @@ composer require --dev smeghead/php-vendor-credits
 ## Usage
 
 ```bash
-$ vendor/bin/php-class-diagram . > CREDITS
+$ vendor/bin/php-vendor-credits . > CREDITS
 ```