readme usage

README.md

@@ -1,5 +1,6 @@
 # Mailer
 ## A PHP Mailer library
+Mailer is a super simple mail package wrapping the Symfony `SwiftMailer`
 ### Dependencies
 This package -as a standalone- has a dependency that has to be manually installed. This of course applies if your app doesn't already have it installed.  
 
@@ -19,3 +20,17 @@ MAIL_PASSWORD
 MAIL_PORT
 MAIL_ENCRYPTION
 ```
+### Usage
+With the helper `mailer()` which is the same as `new MDP\Mailer`
+```php
+mailer()->send($subject, $mailFrom, $nameFrom, $recipients, $body);
+```
+You can add as a sixth parameter the **priority** as an integer, being `1` the highest and `5` the lowest.
+This can be achieved also using the swiftmailer constants:
+```php
+Swift_Mime_SimpleMessage::PRIORITY_HIGHEST; // 1
+Swift_Mime_SimpleMessage::PRIORITY_HIGH; // 2
+Swift_Mime_SimpleMessage::PRIORITY_NORMAL; // 3
+Swift_Mime_SimpleMessage::PRIORITY_LOW; // 4
+Swift_Mime_SimpleMessage::PRIORITY_LOWEST; // 5
+```