Heroku automatically changing state from up to down
<p>I have default node-js starting script and Twitch bot on my Dyno.
But every hour I'm getting in my logs:</p>

<pre><code>2016-04-25T20:28:10.328746+00:00 heroku[web.1]: State changed from up to down
2016-04-25T20:28:10.327874+00:00 heroku[web.1]: Idling
2016-04-25T20:28:13.451043+00:00 heroku[web.1]: Stopping all processes with SIGTERM
2016-04-25T20:28:15.026707+00:00 heroku[web.1]: Process exited with status 143
</code></pre>

<p>Why is this happening? How do I prevent Heroku from changing the state?</p>