title: Devise/Rails - How to remove a particular flash message? (Signed in Successfully)
body: <p>Using Devise, I would like to know if there is a way to remove a particular flash message? (Signed in Successfully).</p>
  
  <p>I care about other msg in the view, so It is just for the signed in and the signed out one.
  Did I have to overwrite the controller or there is another way?</p>
  
  <p>Thank you!</p>