Add info on tests

Author: anantn

README.md

@@ -8,7 +8,7 @@ Example
 -------
 ```php
 <?php
-  include_once 'JWT.php';
+  include_once 'Authentication/JWT.php';
 
   $key = "example_key";
   $token = array(
@@ -25,6 +25,19 @@ Example
 ?>
 ```
 
+Tests
+-----
+Run the tests using phpunit:
+
+```bash
+    $ pear install PHPUnit
+    $ phpunit tests/
+    PHPUnit 3.7.10 by Sebastian Bergmann.
+    .....
+    Time: 0 seconds, Memory: 2.50Mb
+    OK (5 tests, 5 assertions)
+```
+
 License
 -------
 [3-Clause BSD](http://opensource.org/licenses/BSD-3-Clause).