How do I access RStudio on a Shiny server with default config?

[cervus]

I've got two Shiny servers (AWS EC2).

1. The first server is configured to run as :HOME_USER:

/etc/shiny-server/shiny-server.conf

run_as shiny;
server {
  listen 3838 127.0.0.1;
  run_as :HOME_USER:;
  location / {
    user_dirs;
  }
}

When I open the root directory in the browser, I get RStudio, which is very handy.

2. The second server has the default configuration

*/etc/shiny-server/shiny-server.conf *

# Instruct Shiny Server to run applications as the user "shiny"
run_as shiny;
preserve_logs true;

# Define a server that listens on port 3838
server {
  listen 3838;

  # Define a location at the base URL
  location / {

    # Host the directory of Shiny Apps stored in this directory
    site_dir /srv/shiny-server;

    # Log all Shiny output to files in this directory
    log_dir /var/log/shiny-server;

    # When a user visits the base URL rather than a particular application,
    # an index of the applications available in this directory will be shown.
    directory_index on;
  }
}

I like this option, as it makes for shorter URLs. The only problem is that, when I open the root directory of this server in the browser, I get the index page listing the Shiny apps.

How can I get to RStudio?