diff --git a/.travis.yml b/.travis.yml
index 2e3480a..9d77e7b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,3 +5,7 @@ services:
 
 script:
   - make test
+
+branches:
+  only:
+    - master
diff --git a/Dockerfile b/Dockerfile
index 418e32e..5ba6cb9 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,5 +2,5 @@ FROM php:5.5.37-fpm
 RUN curl -O https://getcomposer.org/composer.phar
 RUN mv composer.phar /usr/local/bin/composer
 RUN chmod a+x /usr/local/bin/composer
-RUN pecl install xdebug && docker-php-ext-enable xdebug
+RUN pecl install xdebug-2.5.5 && docker-php-ext-enable xdebug
 RUN apt-get update && apt-get  install -y git unzip
diff --git a/src/LineItems/AbstractLineItem.php b/src/LineItems/AbstractLineItem.php
index 685d6ff..550b651 100644
--- a/src/LineItems/AbstractLineItem.php
+++ b/src/LineItems/AbstractLineItem.php
@@ -1,23 +1,24 @@
-<?php
-
-namespace ChartMogul\LineItems;
-
-/**
-* @codeCoverageIgnore
-* @property-read string $uuid
-*/
-abstract class AbstractLineItem extends \ChartMogul\Resource\AbstractModel
-{
-
-    protected $uuid;
-
-    public $type;
-    public $amount_in_cents;
-    public $quantity;
-    public $discount_amount_in_cents;
-    public $discount_code;
-    public $tax_amount_in_cents;
-    public $external_id;
-
-    public $invoice_uuid;
-}
+<?php
+
+namespace ChartMogul\LineItems;
+
+/**
+* @codeCoverageIgnore
+* @property-read string $uuid
+*/
+abstract class AbstractLineItem extends \ChartMogul\Resource\AbstractModel
+{
+
+    protected $uuid;
+
+    public $type;
+    public $amount_in_cents;
+    public $quantity;
+    public $discount_amount_in_cents;
+    public $discount_code;
+    public $tax_amount_in_cents;
+    public $transaction_fees_in_cents;
+    public $external_id;
+
+    public $invoice_uuid;
+}