add ClientId to checksum

Author: nikoloff

lib/Paymill/Models/Request/Checksum.php

@@ -121,6 +121,8 @@ class Checksum extends Base
      */
     private $_handling_amount;
 
+    private $_clientId;
+
     /**
      * Creates an instance of the checksum request model
      */
@@ -129,6 +131,18 @@ function __construct()
         $this->_serviceResource = 'checksums/';
     }
 
+    public function setClientId($clientId)
+    {
+        $this->_clientId = $clientId;
+
+        return $this;
+    }
+
+    public function getClientId()
+    {
+        return $this->_clientId;
+    }
+
     /**
      * Set amount
      *
@@ -582,6 +596,10 @@ public function parameterize($method)
                     $parameterArray['handling_amount'] = $this->getHandlingAmount();
                 }
 
+                if($this->getClientId()) {
+                    $parameterArray['client_id'] = $this->getClientId();
+                }
+
                 // Unite params:
 
                 if($this->getAppId()) {