title: Collecting users who reacted to a message using discord.js
body: <p>I'm trying to collect all users that have reacted to certain message.
  My code</p>
  
  <pre><code>client.on('messageReactionAdd', (reaction, user) =&gt; {
      if(reaction.emoji.name === "✅") {
      console.log(reaction.emoji.users);
  }
  </code></pre>
  
  <p>But it returns undefined. If I use "reaction.emoji" it returns </p>
  
  <pre><code>ReactionEmoji {
    reaction: 
     MessageReaction {
       message: 
        Message {
          channel: [Object],
          id: '371695165498458115',
          type: 'DEFAULT',
          content: 'bb',
          author: [Object],
          member: [Object],
          pinned: false,
          tts: false,
          nonce: '371695172469129216',
          system: false,
          embeds: [],
          attachments: Collection {},
          createdTimestamp: 1508689433217,
          editedTimestamp: null,
          reactions: [Object],
          mentions: [Object],
          webhookID: null,
          hit: null,
          _edits: [] },
       me: true,
       count: 1,
       users: Collection { '370300235030986752' =&gt; [Object] },
       _emoji: [Circular] },
    name: '✅',
  </code></pre>
  
  <p>I'm trying to get the <code>users: Collection { '370300235030986752' =&gt; [Object] },</code> part. Thanks in advance. </p>