Support a SiteValetDriver in the site path

Author: jasonvarga

cli/drivers/ValetDriver.php

@@ -42,7 +42,13 @@ abstract public function frontControllerPath($sitePath, $siteName, $uri);
      */
     public static function assign($sitePath, $siteName, $uri)
     {
-        $drivers = static::driversIn(VALET_HOME_PATH.'/Drivers');
+        $drivers = [];
+        
+        if ($customSiteDriver = static::customSiteDriver($sitePath)) {
+            $drivers[] = $customSiteDriver;
+        }
+        
+        $drivers = array_merge($drivers, static::driversIn(VALET_HOME_PATH.'/Drivers'));
 
         $drivers[] = 'LaravelValetDriver';
 
@@ -71,6 +77,23 @@ public static function assign($sitePath, $siteName, $uri)
             }
         }
     }
+    
+    /**
+     * Get the custom driver class from the site path, if one exists.
+     *
+     * @param  string  $sitePath
+     * @return string
+     */
+    public static function customSiteDriver($sitePath)
+    {
+        if (! file_exists($sitePath.'/SiteValetDriver.php')) {
+            return;
+        }
+        
+        require_once $sitePath.'/SiteValetDriver.php';
+        
+        return 'SiteValetDriver';
+    }
 
     /**
      * Get all of the driver classes in a given path.