Update README.md to include Local Pest (#30)

Added description to setup Local Pest Integration settings.

README.md

@@ -26,5 +26,22 @@ This plugin adds support for using Pest PHP inside PHPStorm
 
   Then search for the plugin and install it as usual.
 
+## Configuration
+
+To configure pest to run properly, you need to setup the the proper local test framework
+
+- Navigate to
+
+  <kbd>Preferences</kbd> > <kbd>Languages & Frameworks</kbd> > <kbd>PHP</kbd> > <kbd>Test Frameworks</kbd>
+
+  And add the following two configuration fields:
+
+  Set "Path to Pest Executable" to
+	<code>/path/to/your/project/vendor/pestphp/pest/bin/pest/</code>
+
+  Set the "Test Runner" to
+	<code>/path/to/your/project/phpunit.xml</code>
+
+
 ---
 Plugin based on the [IntelliJ Platform Plugin Template](https://github.com/JetBrains/intellij-platform-plugin-template).