Boxcab is an easy to use CMS for applications hosted on Heroku. It allows non-tech people to edit the content of static pages through a nice UI. See it as PerchCMS for Heroku applications.
There is nothing to host, no migration to run. It works with Rails 3, Rails 4 and Rails 5.
Usually we're talking about the "about us", "our team", contact us", etc. pages in your Rails application. In some cases, we can extend this definition to the index page.
There are many ways to handle them. You can either roll your own system like described in this article http://blog.teamtreehouse.com/static-pages-ruby-rails or use a gem like HighVoltage.
The awesome thing is that Boxcab is pretty agnostic about your system.
Your application has to run on Heroku. Besides, you have to add the Boxcab add-on.