Unfortunately, I do not have much information on Fedena as it is not something that I have ever worked with. Ruby on Rails can be installed on a VPS in which I recommend opening a ticket with our Technical Support team for a quote as well as to have the installation completed.
When looking into Fedena, it does look like the installation is done primarily through the Linux command line which I do highly recommend that you have some experience with Linux prior to attempting the installation. If not, perhaps they have an installation service that you could use or possibly another developer out there that could complete the installation for you. If you would like to attempt it after Ruby on Rails is installed, you may locate their documentation on the installation process at the following:
Fedena installation documentation