Some updates

src/SmsGateway/SenderInterface.php

@@ -3,4 +3,12 @@ namespace SmsGateway;
 
 interface SenderInterface
 {
-}
+    /**
+     *
+     * @param  string $recipient
+     * @param  string $message
+     * @return boolean           true upon success. On error, throws exceptions.
+     * @throws Exception         Upon sending error. Gnokii output will be
+     *                           stored in $e->message
+    public function send($recipient, $message);
+}