How can I do if a user click a button then he can have bookmark of website in mobile home screen? Using Rails and Bootstrap

I have a strategy:

1. If a user come to welcome page using his smartphone, he can click a button like Get Bookmark to my phone! then he can view the bookmark icon of my website on his smartphone home screen.

2. And then the user can just click the bookmark from his mobile home screen.

Is it possible? I am using Rails 4 and Bootstrap.

I want to the Get Bookmark to my phone! appear only user using small devices.