title: Run a cron job set up in Wordpress from external source
body: <p>I currently use WP-Crontrol plugin to create, schedule, and run a few cron jobs in a Wordpress environment.  When using this, everything runs smoothly.  My question is:  How can I run the cron job from an external app or http request?  </p>
  
  <p>Primarily, I'd like to be able to trigger to run the cron from a Slack /command.  I can't seem to determine what the URL of the request would be, or if this is even possible.</p>
  
  <p>The action hook is "run_post_sync".  </p>