Automatically apply bootstrap style to devise view files

Conclusion

$ rails g devise:views:bootstrap_templates -f

This will automatically apply the bootstrap style to all devise view files.

Prepare a little more

Code written by default in the devise view file

<div class="container">
  <div class="row">
    <div class="mx-auto" style="width: 580px;">

    </div>
  </div><!-- End of row -->
</div><!-- End of container -->

If you surround it with this,

Good vibes!