Build multi-arch container images across stack
diff --git a/apps/maddy/web/Dockerfile b/apps/maddy/web/Dockerfile
index 8c057e1..0b38e18 100644
--- a/apps/maddy/web/Dockerfile
+++ b/apps/maddy/web/Dockerfile
@@ -1,4 +1,6 @@
 FROM giolekva/maddy:v0.4.4 AS maddy
 
-COPY maddy-web /usr/bin
+ARG TARGETARCH
+
+COPY maddy-web_${TARGETARCH} /usr/bin/maddy-web
 RUN chmod +x /usr/bin/maddy-web