title: how to change mail link in devise from localhost to herokuapp?
body: <p>I have rails app and i have hosted in heroku. when the user is created devise sends a confirmation to the mail where clicking on the link will cofirm the user account. The problem is the link in the mail points to localhost instead of herokuapp.com, so how can i change the link from localhost to herokuapp.com. Please help me</p>
  
  <p>the link in the mail points to </p>
  
  <pre><code>http://localhost:3000/signup/confirmation?confirmation_token=sdgfshtdf364wygd
  </code></pre>
  
  <p>but i want the link to point to</p>
  
  <pre><code>http://example.herokuapp.com/signup/confirmation?confirmation_token=sdgfshtdf364wygd 
  </code></pre>