This gem packages the intl-tel-input assets (JavaScripts, stylesheets, and images) for the Rails asset pipeline.
Check the original documentation here: https://github.com/jackocnr/intl-tel-input
Include the gem in your Gemfile:
gem 'intl-tel-input'
Add the following to your application.js:
//= require intl-tel-input
Also add to your application.css:
/*
*= require intl-tel-input
*/