Add user jenkins to docker group
diff --git a/Dockerfile b/Dockerfile
index b726dc9..4d53e32 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -66,6 +66,7 @@
     apt-get update && \
     apt-get install --no-install-recommends -y docker-engine && \
     apt-get clean && rm -rf /var/lib/apt/lists/*
+RUN adduser jenkins docker
 
 USER ${user}