title: Select from multiple tables in sequelize
body: <p>I'm struggling in how to select from two tables using the Sequelize.</p>
  
  <p>Actually I'm trying to do it:</p>
  
  <pre class="lang-sql prettyprint-override"><code>SELECT * FROM users, clients WHERE user.id = clients.user_id
  </code></pre>
  
  <p>I have no idea how to user two tables as I described, the only thing I did that got some results were:</p>
  
  <pre class="lang-js prettyprint-override"><code>const clients = await Client.findAll({
      attributes: ["user_id"],
  });
  
  const users = [];
  for (const client of clients) {
      let user = await User.findAll({
          where: {
              id: {
                  [Op.eq]: client.user_id
              }
          }
      });
      users.push(user);
  }
  </code></pre>
  
  <p>Which return me something:</p>
  
  <pre><code>[
      [
          {
              "id": 1,
              "first_name": "Velda",
              "middle_name": "Zboncak",
              "last_name": "Kris",
              "email": "vkris10@hotmail.com",
              "created_at": "2020-02-07T20:09:29.484Z",
              "updated_at": "2020-02-07T20:09:29.484Z"
          }
      ]
  ];
  </code></pre>