Codes Only.

kakao_story.js

$(document).on("turbolinks:load", function (){
    if ( $('#kakaostory-share-button').length > 0 ) {
        Kakao.Story.createShareButton({
      container: '#kakaostory-share-button'
    });
  }
});

application.html.erb

<head>
    <%= render 'layouts/kakao-sdk' %>
    ...
</head>
<body>
    <%= render 'layouts/kakao-sdk-init' %>
    ...

_kakao-sdk-init.html.erb

<script type='text/javascript'>
  if ( typeof Kakao != "object") {
    Kakao.init(ENV["KAKAO-JS-KEY"]);
  }
</script>

_kakao-sdk.html.erb

<script src="//developers.kakao.com/sdk/js/kakao.min.js"></script>