Add a little CPS optimizer

Dockerfile

@@ -3,6 +3,7 @@ COPY . .
 RUN echo ":8000" > /etc/caddy/Caddyfile
 RUN echo "rewrite /repl /repl.html" >> /etc/caddy/Caddyfile
 RUN echo "rewrite /compilerepl /compilerepl.html" >> /etc/caddy/Caddyfile
+RUN echo "rewrite /cpsrepl /cpsrepl.html" >> /etc/caddy/Caddyfile
 RUN echo "log" >> /etc/caddy/Caddyfile
 RUN echo "file_server" >> /etc/caddy/Caddyfile