title: Modify a value inside a rails mongoid query
body: <p>I am storing phone numbers in the database in the user model in various formats. All the followings are possible.</p>
  <pre><code>+306974135662, 306974135662, 30 6974135662
  </code></pre>
  <p>Then from the front-end, I am getting a specific format that has the plus sign and no spaces.</p>
  <pre><code>+306974135662
  </code></pre>
  <p>I want to write a mongoid query that matches all the above formats. Is that possible?</p>
  <pre><code>User.where(phone: params[phone])
  </code></pre>
  <p>should return all 3 users with phone numbers +306974135662, 306974135662, and 30 6974135662</p>