diff --git a/flask/app/Dockerfile b/flask/app/Dockerfile
index d0be3b5..a62b9b2 100644
--- a/flask/app/Dockerfile
+++ b/flask/app/Dockerfile
@@ -14,14 +14,10 @@ CMD ["app.py"]
 
 FROM builder as dev-envs
 
-RUN <<EOF
-apk update
-apk add git
-EOF
+RUN apt update && \
+apt add git
 
-RUN <<EOF
-addgroup -S docker
+RUN addgroup -S docker && \
 adduser -S --shell /bin/bash --ingroup docker vscode
-EOF
 # install Docker tools (cli, buildx, compose)
 COPY --from=gloursdocker/docker / /