title: Discord.JS get member from user ID
body: <p>I'm pretty new to Discord.js and Stackoverflow. So I don't know exactly how to do this.</p>
  <p>I do know that this question has been asked many times, sadly any I've found haven't worked.</p>
  <p>I'm trying to assign roles to members on their birthday. I want to do this with a crontab.
  Now I have their user ID's but sadly when I request the member with this code.</p>
  <pre><code>let guild = client.guilds.cache.get('Guild ID');
  let member = guild.members.cache.get('User ID');
  console.log(member);
  </code></pre>
  <p>I just get an <code>undefined</code> message. Now I know that the user ID is correct. I just don't know why I get the <code>undefined</code> message.</p>