title: How to create unique indexes in Laravel?
body: <p>I create table with migration in laravel 5.6.</p>
  
  <p>I need create a unique indexes with migration.</p>
  
  <p>My code is:</p>
  
  <pre><code>$table-&gt;index([
              'system',
              'code',
              'city',
              'seat',
              'type'
          ], 'PrimaryPayment');
  </code></pre>
  
  <p>But after run <code>migrate</code> . in <code>phpmyadmin -&gt; table -&gt; table_name -&gt; indexes</code> show <code>unique: No</code></p>
  
  <p>How to create unique indexes?</p>