Make supervisor log its children stdout/stderr to its own stdout/stderr

docker/supervisor/asciinema.conf

@@ -3,9 +3,15 @@ nodaemon=true
 
 [program:nginx]
 command=/usr/sbin/nginx -g "daemon off;"
-redirect_stderr=true
+stdout_logfile=/dev/stdout
+stdout_logfile_maxbytes=0
+stderr_logfile=/dev/stderr
+stderr_logfile_maxbytes=0
 
 [program:rails]
-command=bundle exec unicorn -p 3000 -c config/unicorn.rb
-redirect_stderr=true
-directory=/app
+command=bundle exec unicorn -c config/unicorn.rb
+directory=/app
+stdout_logfile=/dev/stdout
+stdout_logfile_maxbytes=0
+stderr_logfile=/dev/stderr
+stderr_logfile_maxbytes=0