title: Query for records with empty array with Rails and Postgres array type?
body: <p>How can I query for all records with an empty array, using the Postgres array data type? </p>
  
  <pre><code> create_table "users", force: :cascade do |t|
     t.string   "email", limit: 255, default: "",null: false
     t.string   "roles", default: [], array: true
   end
  </code></pre>
  
  <p>I want to query for all records with an empty roles array.</p>
  
  <p>Tried <code>User.where("roles @&gt; ?", '{}')</code> but that did not work (returned 0 records).</p>