diff --git a/Dockerfile b/Dockerfile
index b7fde32..e7f2319 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM ruby:alpine as base
+FROM ruby:alpine AS base
 
 WORKDIR /app
 
@@ -23,7 +23,7 @@ RUN <<EOT
   bundle install
 EOT
 
-FROM build as dev
+FROM build AS dev
 
 WORKDIR /app