Dockerize the app to enable Kamal deployments [WIP]

[mediafinger]

Dockerize

Created a new Rails 7.1.3 app under Ruby 3.3.1 and copied the three Docker config files. Apart from that followed the tutorial at:

• https://www.shakacode.com/blog/rails-7-1-adds-default-dockerfiles/

TODOs

• [ ] See comments in Gemfile and fix issue
• [ ] adapt Docker config files to yournaling's needs
• [ ] run docker scout quickview and fix potential issues