title: Multiple select in Material Table
body: <p>I want to have a multiple select when editing a row. This is currently what I have</p>
  <p><img src="https://i.stack.imgur.com/epaTp.png" alt="My current table" /></p>
  <p>I want to change it to multiple select, and whenever I add more items, it gets appended to the Tank column as a string. This is the code for my columns :</p>
  <pre><code>    const columns = [
      {
          title: &quot;Level&quot;,
          field: 'sequence',
          editable: 'onAdd',
      },
      {
          title: 'Tank',
          field: 'tankNo',
      },
      {
          title: &quot;Select &quot;,
          field: 'tankNo',
          lookup: { 'test1': 'select1', 'test2': 'select2' }
      }
  ];
  </code></pre>