title: rails ransack gem to search json column
body: <p>I have a field as json column and i have to search all the phone values inside that column, i have searched for it and i have not found any document using ransack. Is it possible to use ransaack to search json column?
  I have used the ransack to search other fields, so i have to use ransack or something that can combine both result</p>
  
  <p>my json column looks like this</p>
  
  <pre><code>{"phone1"=&gt;"", "relationship_type1"=&gt;"", "relationship_name1"=&gt;"", "phone2"=&gt;"", "relationship_type2"=&gt;"", "relationship_name2"=&gt;"", "phone3"=&gt;"", "relationship_type3"=&gt;"", "relationship_name3"=&gt;"", "phone4"=&gt;"", "relationship_type4"=&gt;"", "relationship_name4"=&gt;""}
  </code></pre>
  
  <p>phone1, phone2,3,4 should be searcheable.</p>