Added HasVendor

src/Builders/Bill.php

@@ -2,9 +2,10 @@
 
 namespace ReneDeKat\Quickbooks\Builders;
 
+use ReneDeKat\Quickbooks\Builders\Traits\HasVendor;
 use ReneDeKat\Quickbooks\Builders\Traits\Itemizable;
 
 class Bill extends Builder
 {
-    use Itemizable;
+    use HasVendor, Itemizable;
 }

src/Builders/Traits/HasVendor.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace ReneDeKat\Quickbooks\Builders\Traits;
+
+trait HasVendor
+{
+    /**
+     * Set Vendor's ID.
+     *
+     * @param int $id Vendor's Quickbooks ID
+     *
+     * @return $this
+     */
+    public function setVendor($id)
+    {
+        $this->data['VendorRef']['value'] = $id;
+
+        return $this;
+    }
+}