diff --git a/Dockerfile b/Dockerfile
index c88af6cfe4e..f32220d6291 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -19,3 +19,4 @@ WORKDIR /home/linuxbrew
 ENV PATH=/home/linuxbrew/.linuxbrew/bin:/home/linuxbrew/.linuxbrew/sbin:$PATH \
 	SHELL=/bin/bash \
 	USER=linuxbrew
+RUN brew config # install portable-ruby