Merge pull request #21 from max-si-m/patch-1

Update README.md

Author: beardyman

README.md

@@ -20,6 +20,7 @@ composer require sparkpost/php-sparkpost
 After installing, you need to require Composer's autoloader:
 ```
 require 'vendor/autoload.php';
+use SparkPost\SparkPost;
 ```
 
 ## Getting Started:  Your First Mailing