Site URL for Facebook Like Button on Rails/Heroku: works on box but not on Heroku

I've been trying to solve a site URL problem for Facebook-Like Button (similar to here site URL for the facebook like button), but mine is specific to Rails or Heroku.

In rails I set the data-href in the html5 script to dynamic url:

da开发者_运维知识库ta-href="<%= post_url(post) %>" data-send="false" data-layout="button_count" data-width="100" data-show-faces="false"

From my box this works fine, capturing domain.com/posts as the url, but when deployed to Heroku, Facebook only picked up the domain.com

My Linter/Debugger passes with no issues.