title: How do I add default value as same from another column in Laravel Migration
body: <p>I have a <code>questions</code> table in my database, in which I have a column of <code>question_title</code>, now I have added a column <code>question_slug</code>, which will contain the  <strong>question's slug URL</strong>, so how I set <code>question_slug</code> default value as <code>question_title</code> in Laravel Migration, I need this all because I have questions saved in the database so I have run <code>php artisan make:migration add_column_to_questions --table=questions</code> now I have this code:</p>
  
  <pre><code>Schema::table('questions', function (Blueprint $table) {
      $table-&gt;string('question_slug')-&gt;default();
  });
  </code></pre>