title: how to save array to database in rails
body: <p>if i have params like this :</p>
  
  <pre><code>params["scholarship"] = {"name"=&gt;"test", "state_ids"=&gt;["1", "2", "3", "4"]}
  </code></pre>
  
  <p>and when i create object to database field state_id not save to database?    </p>
  
  <p>how to save to database with format :</p>
  
  <pre><code>#&lt;Scholarship id: 1, name: "test", state_id: "["1", "2", "3", "4"]"&gt;
  </code></pre>
  
  <p>how do that?</p>
  
  <p>thanks before</p>