THRIFT-4423: migrate to psr-4
Client: php

This closes #1445
diff --git a/build/docker/ubuntu-artful/Dockerfile b/build/docker/ubuntu-artful/Dockerfile
index 831e347..59bbfa9 100644
--- a/build/docker/ubuntu-artful/Dockerfile
+++ b/build/docker/ubuntu-artful/Dockerfile
@@ -24,8 +24,8 @@
 MAINTAINER Apache Thrift <dev@thrift.apache.org>
 ENV DEBIAN_FRONTEND noninteractive
 
-RUN apt-get update && \ 
-    apt-get dist-upgrade -y && \ 
+RUN apt-get update && \
+    apt-get dist-upgrade -y && \
     apt-get install -y --no-install-recommends \
       apt \
       apt-transport-https \
@@ -188,7 +188,7 @@
       php-dev \
       php-pear \
       re2c \
-      phpunit
+      composer
 
 RUN apt-get install -y --no-install-recommends \
 `# Python dependencies` \