title: Error when deploying shinystan using shiny server
body: <p>I'm trying to use the shinystan package to build a dashboard that shows diagnostics for stan models. I have the following code in an app.R file deployed to an ec2 instance.</p>
  <pre><code># shiny stan app
  
  library(shiny)
  library(shinystan)
  library(rstan)
  
  chain1 &lt;- rstan::read_stan_csv('data/chain1.csv')
  chain2 &lt;- rstan::read_stan_csv('data/chain2.csv')
  
  my_sso &lt;- sflist2stanfit(c(chain1, chain2))
  my_sso &lt;- as.shinystan(my_sso, model_name = &quot;Test&quot;)
  launch_shinystan(my_sso)
  </code></pre>
  <p>The shinystan dashboard launches when I run this file locally in rstudio, but I get an error when I check the logs for my app in shiny server.</p>
  <p>Here's the error I get in the logs:</p>
  <pre><code>Launching ShinyStan interface... for large models this  may take some time.
  
  Listening on http://127.0.0.1:5801
  /usr/bin/xdg-open: 882: www-browser: not found
  /usr/bin/xdg-open: 882: links2: not found
  /usr/bin/xdg-open: 882: elinks: not found
  /usr/bin/xdg-open: 882: links: not found
  /usr/bin/xdg-open: 882: lynx: not found
  /usr/bin/xdg-open: 882: w3m: not found
  xdg-open: no method available for opening 'http://127.0.0.1:5801'
  
  
  Execution halted
  </code></pre>