I managed to add ‘Facebook Login’ functionality to my Ruby on Rails project and it works well with the Site URL pointing to my local development environment (e.g, http://www.dev.project.com:3000). However, when pushing my code to the production server, the Site URL set in the Facebook App has to be changed accordingly (e.g., http://www.project.com). After that, the Facebook Login works for the production environment, but not anymore in my local development environment.
In other words, is it possible to specify multiple Site URLs for a single Facebook App, or do I really have to create a new Facebook App for every development environment?
Nowadays you can add multiple domains for your Facebook application. This should solve this issue.